Already extremely important in Etruscan times, Chiusi experienced its period of maximum splendour during the era of the legendary King Porsenna. Important findings, the results of archaeological excavations which are still successfully carried on, can be viewed in the "National Etruscan Archaeological Museum". Standing in front of the museum is the Duomo, already existing in the twelfth century and transformed in 1585. The Cathedral Museum, erected next door in the thirties, conserves important findings including precious engraved missals.
Etruscan tombs have also been brought to light here, like the Scimmia, Leone, and Pania tombs and many others as well. Christianity spread through these areas very quickly as testified to by the Catacombs of Santa Mustiola and Santa Caterina.
Apart from the catacombs, the "Labyrinth of Porsenna" can also be visited with its intricate underground tunnel system that leads to the Cistern dating back to the first century BC. For all these reasons, and also thanks to its considerable natural beauty, Chiusi is rapidly developing its own tourist vocation. Another important attraction is represented by the Lake of Chiusi, downhill from the city, a tranquil mirror of water where it is possible to go competition fishing.