Frasassi Caves

Italy's great show cave, in the hills of the Marche, where the Grotta Grande del Vento was only discovered in 1971. It is best known for the Abisso Ancona, a chamber so large it is often said to have room for Milan Cathedral. The standard guided walk takes about an hour and a quarter at a steady 14°C, and the operator describes it as accessible to all. What lifts Frasassi above a standard tourist cave is the extra tier: two speleo-adventure tours let visitors go beyond the lit path without joining a caving club. Start with the standard route, and book the adventure version only if the giant chamber leaves you wanting more.