This fine Gothic building is made up of three vast naves with a triforium. The superb foliage decoration dates from the 16C. You will see some fine works of art here including a magnificent pulpit dating back to the 19C. The treasury room contains the bust-reliquary of St Lambert, in vermeil, which stands on a plinth illustrating scenes from the Saint's life. A word to the wise - every 50 years, they open the reliquary to check that the skull is still in good condition.