In the very heart of Sri Lanka, a massive flat-topped, sheer-sided rock rises abruptly from the plains. It is a striking sight and a remarkable one due to the presence on its summit of an unusual fortress built in the 5th century. About halfway up the great rock, recessed into a kind of niche, are a series of celebrated frescoes depicting women often referred to as apsaras – celestial nymphs, or ‘cloud maidens’ – but possibly depicting the king’s wives and courtesans bathing or tending flowers. Exhilarating stairs and precipitous catwalks complete the final haul to the summit, which is rewarded with marvellous views across the serene countryside. For many visitors, this is understandably the country’s top cultural attraction.