With its rolling hills and uninspiring towns, the central part of northern Bulgaria appears unexciting and dull, a place you pass through on your way to somewhere else. However, as so often happens in Bulgaria, appearances are deceiving. Detour from the Sofia-Varna highway when you see the signs to Lovech and in the plateau that starts east from town you will find an unknown world of windswept hills, fertile farmland, sleepy villages and impressive natural phenomena. Welcome to the world of Devetaki Plateau.

The Krushuna Waterfalls is one of the best known highlights. Located by the eponymous village, near the town of Letnitsa, the waterfalls started to attract visitors in the 2000s, when an eco trail was built around them.

The Krushuna Waterfalls is a cascade carved by the Proynovska River into the soft travertine rock, the largest formation of this sort in Bulgaria.

Krushuna Waterfalls

Emerging from a large and menacing cave called Maarata, the first waterfall is also the highest. It cascades from 15m, and is also the only one with its own name, Praskaloto, or The Sprinkler. The rest of the falls remain nameless, but you do not need names to appreciate the surreal beauty of this maze of constantly running water, small basins and thick moss hanging from strange rock formations, blurry in the damp mist. The atmosphere is almost tropical, a tamed Valdivian rainforest ready for exploration by the weekend visitor.

Man-made niches cover the rocks around the waterfalls, the only sign that in the Middle Ages monks used to call the cascade home. Here, they practiced Hesychasm, a mystic Eastern Orthodox tradition prescribing personal salvation through contemplative prayer.

The history of the area runs deeper. Nearby Letnitsa is where one of the most fascinating Thracian treasures was found: a set of gold and silver wedding decorations depicting the life of a Thracian deified king. The town itself is unexciting, but 2 kilometres beyond there is another waterfall. The Urushki Waterfall is 20m high and has the same tropical feel as the ones in Krushuna. It, too, springs from a cave, the Urushka Maara. In the past Yuruk nomadic shepherds used to keep their flocks there, hence the name.

Devetaki Cave

About 7 kilometres from Letnitsa, however, there is a much more spectacular cave: the Devetaki Cave. Its majestic main cavern rises up to 58 m and covers an area of almost an acre, making it the largest of its kind in the eastern Balkans, but it is not only its sheer size that awes visitors to the cave. Seven openings, large and small, pierce the rock dome of the main cave, sending eerie shafts of light into the void. A spring murmurs through the cavity, its voice mingling with the squeaks of swallows and shrieks of bats.

When people took notice of the Devetaki Cave for the first time, they were attracted more by its suitability as a place of habitation rather than by its majestic beauty. Both Neanderthals and early Homo sapiens lived in the cave. This trend continued from the Neolithic times well into Antiquity, and even as late as the mid-20th century locals saw the Devetaki Cave as nothing more than a convenient sheep shelter.

In the 1950s, the Warsaw Pact Bulgarian Army went a step further. Archaeologists had already recognised the historical importance of the cave, yet the location was deemed too good a site for a classified fuel storage facility to be left to itself. Concrete tanks were built in the cave and a military base sprang up by the entrance. The site was declared a historical monument in 1967, yet it remained strictly off-limits until the army moved out in the early 1990s. The only remnant of the Communist army now is... the stink of petrol and motor oil that still permeates the soft floor of the cave.

Probably because of this, the legends told about the Devetaki Cave are concerned with modern times. One of these insists that the Germans used the cave as a munitions depot during the Second World War. When the Wehrmacht withdrew from Bulgaria, it was unable to take the munitions, so a decision was made to blow up the whole cave. Luckily, the legend goes, a local shepherd stumbled upon the detonation cord and, as he happened to need a bit of wire at the time, cut a piece of it and inadvertently thwarted the demolition.

Another story tells of a reckless pilot who flew into the mouth of the cave and exited through the largest opening in the roof.

One important thing to note: visiting the Devetaki Cave is prohibited in June and July, which is the local bat colony's mating season.

The cinematic potential of the Devetaki Cave was realised in 2012 as Sylvester Stallone, Chuck Norris, Bruce Willis, Arnold Schwarzenegger et all descended on central north Bulgaria to shoot The Expendables 2.

Stalbitsata Cave

Devetaki Plateau has two more caves open for visitors: Garvanitsa, or the Raven's Place, and Stalbitsata, or the Staircase. Both are challenging, in different ways. Stalbitsata is named after the rickety metal staircase that leads to a damp, dark underground cavern lit solely by the light filtering through the narrow entrance.

Garvanitsa is even harder on visitors – the descent into the 60m deep cavern is possible only by a narrow, steep and rickety series of stairs.

For over a decade now the Devetaki Plateau has been developing rural and green tourism. The local villages offer proper guesthouses, and the area contains many more caves, archaeological sites and paths to explore. In summer, there is a popular open air jazz festival. For more information, including upcoming events, check www.devetakiplateau.org.