The Strandzha mountains coast, roughly everything along the Black Sea south of Burgas, is about 100 km long as the crow flies. Yet it is very varied. You will discover smaller and bigger bays, old towns and purpose-built modern resorts, a campsite or two, a number of picturesque rivers, inlets and... islands. In fact all of Bulgaria's islands are along the Strandzha coast. You will probably be underwhelmed, however. There are just four of them, not counting the St Kirik Isle north of Sozopol which was appended to the mainland, in the 20th century, with a quay.

The northernmost isle is St Anastasiya, in the Bay of Burgas. On an area of 0.22 sq km, St Anastasia has accumulated more history than its humble size suggests. It was inhabited at least from the 4th-6th century AD, and in the Middle Ages a monastery was built on it. It survived well into the 20th century.

In late summer, Strandzha's skies fill with storks that gather in large flocks before their journey to Africa

Then something unexpected happened. In 1923, the government closed the monastery and turned the island into a political prison for members of the persecuted Agrarian Party and the Bulgarian Communist Party. In 1925, 43 Communist inmates made a daring escape. The fugitives managed to reach the Soviet Union but soon afterwards most of them fell victim to the Stalinist purges.

Their escape proved inspirational for the Communist government after 1944. St Anastasia was renamed Bolshevik and was repurposed for recreational activities. In the 1960s-1980s, the island became a favourite haunt for both tourists and the Burgas bohemia, who loved the rugged terrain, the marvellous vistas of Burgas Bay, the cheap restaurant and the feeling of a getaway from the over-regulated life on the mainland. The island had become a place to escape to, not to escape from.

With the democratisation after 1989, the island's old name was restored. Due to financial issues, regular transportation was terminated and the restaurant was closed. For years, the only people on St Anastasia were the keepers of the lighthouse, which was first built in 1888, and in 1914 was replaced with the structure still in operation today.

St Anastasiya Island

The end of St Anastasia's desolation came in 2014, when the Burgas City Council brought back the island onto the local tourist map complete with infrastructure, a museum, a hotel and a restaurant.

With its area of 0.66 sq km, St Ivan near Sozopol is Bulgaria's largest sea island. You might have heard its name already, as in 2010 news broke that the "relics" of St John the Baptist had been discovered there. The "holy bones" were unearthed by archaeologists excavating the large monastic compound which was established on the island in the 5th-6th century, and lasted until 1629.

The island has been deserted ever since, if you do not count the Russian military hospital which was operational during the 1828-1829 Russo-Turkish war.

The humble remains of an early Christian basilica on St Ivan Isle were the supposed resting place of some St John the Baptist holy relics

As there are no humans around, the island is a sanctuary of vibrant wildlife. It is a protected area and home to several endangered species. The most interesting are Bulgaria's largest European Herring Gull population and the country's only earth rabbit colony, since 1934. The coexistence between the gulls and the rabbits is far from harmonious. Tiny bones of bunnies eaten by the birds can be seen scattered all over the island. If you visit, try to avoid May, when seagulls nest and may become aggressive to humans.

So close to St Ivan that until recently it was believed to be a part of it, St Petar is only 0.01 sq km in area.

Bulgaria's smallest Black Sea island was probably born after a severe earthquake rocked the island of St Ivan. This catastrophe may have happened around the middle of the 19th century, when the name of the island appeared in historical records for the first time.

Drivers' Beach is one of the last unspoilt beaches in Bulgaria

The islet is more popularly known as Bird Island, because of its Herring Gull colony. This is also the reason for its white colour, the result of accumulated guano.

St Toma, opposite Arkutino, in the Ropotamo Reserve, is the habitat of other rare species. The islet with an area 0.01 sq km bears the name of the chapel which once stood on it, but it is more popularly known as Snake Island. A flourishing colony of grey water snakes live there. They are completely harmless, but can give you a good scare if you are swimming in the bay.

The other peculiarity of Snake Island is the only wild-growing cacti in Bulgaria, introduced here by King Boris III in 1933. The cacti are of the Opuntia variety, and flower in June. In August and September the yellow blossoms produce edible fruits which look like plums and taste of strawberries. St Toma is a part of the Ropotamo Nature Reserve.

St Kirik Isle has been connected with a pier to Sozopol for almost a century

For most visitors the Ropotamo nature reserve, which was founded in 1940, is the shortest cut to Strandzha's raw nature. In it, you can experience both flora and fauna rarely seen elsewhere in Bulgaria, including lianas, water lilies and even sea eagles. St Toma Isle is a small part of the nature reserve. It includes the densely forested lower basin of the River Ropotamo; several nearby beaches; a number of swamps, the most famous of which, Arkutino, sports some of the Black Sea's best beaches. It also has a number of rock attractions like the Lion's Head. The greater Ropotamo reserve also includes the chunk of land north of Primorsko, including the famous Oil Cape.

In summertime the Ropotamo nature reserve is heavily visited. The beaches of Arkutino and Stamopolou have been touristified though to a lesser extent than the ones northwards of the Ropotamo reserve.

The Snake Island is a part of Ropotamo Nature Reserve

During Communism the nature reserve was also popular. Its greatest enemy was... the top Communists themselves. At the end of the 1970s Lyudmila Zhivkova, the daughter of Communist dictator Todor Zhivkov, was minister of culture. She initiated the construction of a huge concrete housing project to give "talented children" the opportunity to meet and be creative. Zhivkova died before the compound was finished. The government still pushed construction until the fall of Communism, in 1989, put the megalomaniacal project to an indefinite hold. Its ruins continue to hover over Arkutino's fine sand dunes.

Under Communism, the area north of Stamopolou was cut off from the outside world by a fence and heavy security. It was turned into hunting grounds for top Communists who spent their holidays at the Perla government residence at the seaside. Perla, now abandoned, still stands. It sport a small but fine beach. Its biggest woe is a badly thoughtover quay erected in the Communist-era. Its purpose was to "protect" the beach from open sea waves. What happens in actual fact is that it also keeps all sediments within the beach area. The result is... a clogged and disappearing sea.

The opening of the Perla residence premises also allowed public access to one of Bulgaria's most fascinating sites. Begliktash, an ancient Thracian rock shrine, stuns with its heavy boulders supposedly arranged millennia ago to measure time, protect the remains of dead kings, serve as the backdrop of sacred rituals and provide spiritual energy.

The mouth of the Ropotamo River

Lovers of wild nature will feel quite at home in Ropotamo. The reserve has many paths, most of them unmarked, that lead to fine beaches and fascinating rock formations.

One of them is Maslen Nos, or Cape Oil, a well-known sight with its emblematic lighthouse. The cape's unusual name comes from the shipwrecks that happened along the treacherous coast. At one point they were so many that the waters around it looked reflective owing to the tons of spilled olive oil from the their holds.

Sozopol and Tsarevo, about 17 km north and 30 km south, respectively, are the largest towns on the Strandzha coast. Both are positioned on rocky promontories and claim long history, particularly Sozopol with its ancient origins and old quarter of traditional houses. In summertime Sozopol and Tsarevo are so packed with tourists that they should be avoided.

Manmade or natural? Begliktash Thracian rock shrine is a stunning place year round

About 20 km south of Tsarevo two settlements defy the mass tourism squads. Ahtopol, Bulgaria's southernmost town at the Black Sea coast, appears to manage the delicate balance between being a relatively inexpensive summer holiday destination and a town that tries to preserve its atmosphere and traditions. If you visit in summertime you will instantly be immersed in the unmistakable atmosphere of middle-class Bulgarian holidaymakers having fun. It will be noisy, overpopulated and the smell of fried fish will be everywhere. Once the crowds go, however, the town retreats back into its shell. The seagulls will continue to cry, but their cries will be melancholic. The only people you are likely to meet are some fishermen who make early morning departures in their boats.

Ahtopol was founded on a rocky peninsula, in 430 BC, as an ancient Greek colony. It was called Agathopolis, the City of Love, and this name still survives in its present form.

Tsarevo's old church

Agathopolis was never on a par with the major powers in the region, like Apollonia (Sozopol). Even in its heyday, when it minted its own coins (in Antiquity) and was the seat of a bishopric (in the Ottoman period), it always had a provincial feel. By the beginning of the 20th century it was a relatively humble but lively fishing community, mostly made up of Greeks who had lived there for generations. After the Balkan Wars of 1912-1913, the majority of them left and were replaced by Bulgarians fleeing the Ottoman Empire. In 1918, disaster struck: a fire ravaged the city, leaving almost nothing of its old houses and archaeological remains.

Under Communism, organised tourism finally reached Ahtopol. But the town lacked the interesting architecture and the fine beaches of its neighbour, Sozopol. Moreover, it was too close to the strictly guarded border zone with Turkey. Most of the organised tourism here consisted of holiday facilities, mainly bungalows, for factory workers. The rest of the business was left to local families who would rent rooms in their houses.

Travelling along this part of the Black Sea coast is easy now, but Ahtopol remains slightly off the beaten track, the resort of blue collar and lower middle class Bulgarians who cannot afford a holiday in more "prestigious" parts of the coast. Some of the old holiday facilities have been abandoned, and new hotels have appeared but local old ladies continue to line up at the entrance of the city, offering rooms to those arriving by bus.

Primorsko's south beach with Perla, the residence of top Communist apparatchiks, in the distance

The holiday-makers in Ahtopol are the very reason why the town remains the quiet, fishing city that is so alluring, with its unpretentious atmosphere.

The oldest part of Ahtopol, on the rocky peninsula, has been almost unchanged for the past 40 years: a labyrinth of narrow streets, low, post-1918 houses, fig trees, cats, old ladies preparing fresh fish and men gathered in their tiny gardens remembering times past, drinking cheap rakiya or mastika.

There are a couple of sights to add to this: the low and dark Church of the Assumption, built in 1776, and the old Greek school, situated on the edge of the wind-blown cliffs. Ahtopol's promenade is one of the most rewarding at the Bulgarian Black Sea coast. Come here for views over a bay filled with colourful fishing boats, for the lonely silhouette of the light signal on an isolated rock in the sea, and for the constant murmur of waves breaking on the cliffs of the peninsula where old Ahtopol stands.

For dramatic vistas, go to Ahtopol's lighthouse during storm

And there is the fish. Ahtopol is the unofficial Bulgarian capital of one of the Black Sea's tastiest and most sought-after fish, palamud, or Black Sea bonito. A migrating species, schools of palamud pass by the southern chunk of the Bulgarian Black Sea coast in autumn. Ahtopol is the place with the greatest concentration of palamud, but the catch is always unpredictable.

A few miles north of Ahtopol the small village of Varvara, which is actually inland, will provide an entirely different standpoint about life along the Black Sea.

According to a local legend, the Varvara village got its name in Antiquity. Back then, wayward Thracians used to live on this rocky part of the Black Sea shore.

Raids and pillage were their main sources of income, and their neighbours, from the rich Greek town of Agathopolis, were their usual victims. As a retribution for the raids, the Greeks called the Thracian settlement Varvara, the place of the Barbarians.

The Iron Tree by Varvara is not a mesmerising piece of land art, but an abandoned movie prop

The story is hardly true. But even if it were, it doesn't fit the profile of modern Varvara. There is hardly more tranquil place to spend a summer vacation on the Bulgarian southern Black Sea coast.

Varvara lacks the shortcomings of its bigger and more popular peers claiming to be seaside resorts. Here there are no crowds of partygoers from all over Europe. The number of fancy bars in Varvara is exactly two, and both of these are on the beach, far from the hotels and the houses. You will struggle to find a souvenir stall. The sidewalks are almost completely for you, and the sky is full with swarms of swallows and storks. Staying and eating in Varvara is relatively cheap and the quality is better than in the more popular seaside resorts at the Strandzha coast like Primorsko, Sozopol, Tsarevo and so on.

Then why is Varvara so calm and affordable?

Because of the sea. The village's only beach is small and rocky. Your other option to swim is to dive from the picturesque cliffs around. The most popular of these are the Dardanelles, named after the Dardanelles straits, and the Mekite Skali, or Soft Rocks.

The iron bridge over the Veleka by Sinemorets was built under Communism to serve military purposes. In case of an attack from Turkey, it could be easily blown up to thwart an invasion

The first tourists to discover the quiet charm of Varvara were the artsy and alternative crowds, which arrived in the early 1980s when travelling to this region, close to Turkey, was still problematic.

Even then, Varvara had the atmosphere of a place out of time and out of space. It is hardly a coincidence that when Bulgarian hippie celebration of the 1 July sunrise went too mainstream in the city of its origins, Varna on the North Black Sea coast, the hardcore revellers moved the event to Varvara. Their meeting point was one of the most surreal landscapes in Bulgaria; a metal tree rising on the windswept shore. The Iron Tree is actually an abandoned movie prop.

While by the early 2000s, Varvara was mainly a place for artists, latterday hippies and everyone outside the mainstream, it gradually started to attract middle-class Bulgarians and hipsters. The feel that you are far from the crowds and that you have all the time in the world to rest is still here and three days in Varvara look like a week (in a good way).

The last two settlements along Strandzha's coast are Sinemorets and Rezovo.

Sinemorets is anything but picturesque – a maze of holiday properties built in the past 20 years – but its surroundings are among the finest on the Bulgarian Black Sea coast. Perched on a rocky peninsula by the mouth of the Veleka River, Sinemorets is surrounded by lush forests and probably the last unspoilt beaches in this country.

The pristine landscape is the result of the Cold War. Under Communism, the village was in the border area with NATO-member Turkey, and access was forbidden without a special permit. This was hardly good for tourism, and the beaches of Sinemorets stayed empty.

Sand lilies

Things changed after 1989. People were now allowed to enjoy the unspoiled nature of Sinemorets. The first to arrive, initially in small groups, were Sofia intellectuals and new-agers seeking refuge from the crowds.

The locals, however, were eager to finally cash in on the beauties of Sinemorets. In the 2000s, construction took over Sinemorets, turning the once sleepy village into a concrete nightmare of new hotels and streets filled with construction debris. The crowds grew bigger and the intellectuals were replaced by ordinary Bulgarians and some German tourists.

The outskirts of Sinemorets remain untouched, as they are part of the Strandzha National Park.

The northern beach at Sinemorets is where the Veleka joins the Black Sea, forming the only fresh water protected bay in Bulgaria. The beach is extremely beautiful – the river flows from the thickly forested slopes of the Strandzha, and empties into the sea through a narrow channel at the northern end of the bay. Picturesque cliffs overlook the spot, and one of them, at the southern end of the bay, is called The Sphinx because it resembles, well, a sphinx.

Swimming at the southern bay at Sinemorets, Butamyata, is easier and it shows. It is more developed, with lines of beach umbrellas on the sand, and a tavern booming out music, and the strong smell of fried fish.

When you are at Butamyata, you might notice a steady stream of people climbing up and down a tiny path in the rocks. Follow them. This is the beginning of the Sinemorets-Rezovo eco path, which leads along the shore and explains, with detailed information boards, the diverse and picturesque geological phenomena sculpted by the sea waves out of volcanic eruptions that occurred about 80 million years ago.

The crowds in the first few kilometres are not interested in the geology as most of them only take the eco path as it leads to the last undeveloped beach on the southern Bulgarian Black Sea.

Silistar is the last piece of sand on the Bulgarian Black Sea coast where you can spread your beach towel

Listi Beach is a long, pristine stretch of sand, protected by rising cliffs, the Strandzha forest and the fact that there is no track leading to it. Nature lovers and campers are a fixture here, staying for days in tents and, when you see the beach, you will understand why.

Silistar Beach, the last on Bulgarian territory, is farther along the eco path, but it can also be reached by car, via the road to Rezovo. It is beautiful, but far more commercialised, with a camping site, a tavern and a forest of umbrellas taking up a good portion of the sand.

If you love walking, there is more around Sinemorets.

Another, and very easy, eco path starts from the northern end of the north beach and leads all the way to Ahtopol. Like the eco path to Rezovo, it incorporates beautiful scenery and more volcanic geology.

For the more adventurous, there is the eco path upstream of the Veleka River. Follow it for the experience of wild forests, clear water and the joy of reaching the village of Brodilovo, deep in the Strandzha, on foot.

Swimming is the last thing to do in Rezovo. The village is located at the northern end of a deep and seductive bay, but most of it is in Turkey. People visit Rezovo mostly for the opportunity to have a selfie in front of the Bulgarian and Turkish flags at the mouth of Rezovska River, defying the sings that ban taking photos of "foreign territory."

The mouth of the Rezovska forms the border with Turkey

In the 1980s, Bulgaria and Turkey were on the verge of a military conflict over the mouth of the Rezovska River. The reason: the middle of the river defines the marine border between the two and the areas where the valuable turbot can be fished. To enhance the chances of their respective fishermen, both countries started to divert the course of the Rezovska by pouring tetrapods into it. When they finally stopped, the mouth of the river had changed beyond recognition, and remains so to this day.

In the 1990s, the Bulgarian government entertained the idea of opening a border crossing point at Rezovo, but this is yet to happen. This is why, when you reach Rezovo, your journey along Strandzha's coast is over.