Once Lisbon’s largest convent and church, it was severely damaged in the great earthquake of 1755 when the roof and arches collapsed on the congregation. Built in almost pure Gothic style, it is an evocative reminder of the devastation. Summer concerts often take place in the ruins. The small archaeological museum, on the site of what used to be the altar, contains a collection of tombs, ceramics, mosaics and statuary and many other artefacts. An engraved stone at the entrance informs you that Pope Clement VII granted 40 days of indulgence to “any faithful Christian” who visits this church.