The hotel guests the English writer Dame Rebecca West described in her 1941 classic Black Lamb and Grey Falcon, were of two kinds: they had seemed as though they had been on a honeymoon, or had been making up for the one they had never had.

But if Dame Rebecca visited Oia on the island of Santorini in 2012, she would regret that she had already used up her irony on the unsuspecting visitors of other Balkan states. The majority of tourists who gather to watch the sunset from Oia – supposedly the best sunset in the world – are in fact on a honeymoon or, at worst, on a romantic trip.

The Oia sunset has been reproduced in countless postcards, magazine covers, tour operator commercials and tourist photos. The island's guests are ready to give a lot to secure the best place for contemplating it. Those thinking strategically arrive in the early afternoon, occupy the most attractive spots at the ruins of the old Venetian fortress tower and never leave their positions until it's dark. Crowds keep gathering every minute till the beginning of the sunset when the mass of people reaches awesome proportions. Tourists seat on every railing and terrace, and block the steep stairs, which in this part of Oia serve as streets. Some enjoy in quiet the delicate change in the colours of the sky, transitioning from light blue to crimson and purple. Others are conversing with friends and relatives on their phones to boast that they are in the middle of watching how the sky is changing its colour, and flood Twitter and Facebook with enthusiastic feeds. A third group are trying to take every second of this daily, grandiose spectacle with cameras and smartphones of all brands, sizes and degrees of professionalism.

But the most enterprising sunset hunters are not in Oia. Some hours earlier they had hired boats, and after a journey across the huge bay of Santorini have stopped at the village's foot just in time for the sunset.

When the red sun touches the horizon of the daisy-blue maritime expanse, accentuating the translucent silhouette of the neighbouring islet of Aspronisi, everyone – in Oia and in the boats – falls silent for a second. Then they resume what they had been doing just a few winks ago: to talk, tweet and make pictures even more fiercely.

Human imagination can have a hard time picturing that the entire romantics-heavy picture is the result of a titanic natural cataclysm. Or, more precisely, of a series of titanic natural cataclysms that started two million years ago.

There were volcanoes where the current island of Santorini is situated, playing restlessly with the earth and the sea. Powerful and weak eruptions were modelling islands in various shapes, and then went on to destroy them only to begin their play anew. Some 30,000 years ago the next of this creation-destruction series started. The pre-historic volcano to which scientists have given the name of Skaros erupted. A ring of solid earth appeared encircling the water-filled surface of the former crater. In the middle of the nearly circular bay that was linked with the sea via a narrow strip of land there was an island.

The island was like that until 1700 BC.