In 1938 speleologist Franco Anelli lowered himself into the "Grave", the sinkhole farmers believed a mouth of hell, and found Italy's most spectacular karst complex: three kilometres of caverns ending at the White Grotto, a dazzling alabaster sanctuary. The full route descends seventy metres beneath the Murgia among columns, drapes and crystals.
The natural light pouring through the Grave at midday is a show within the show.
Our tip: choose the complete itinerary (2 hours), not the short one: the White Grotto lies at the end and is the grand finale. It is cool inside and the floor is damp: shoes with proper soles.