The Basilica of Our Lady of the Martyrs (Basílica de Nossa Senhora dos Mártires) is one of a trio of Rococo / Baroque churches built within a stone's throw of each other on Chiado's Rua da Garrett. This and the other two strikingly similar churches were built in the late 18th century after much of the area was flattened by the great earthquake of 1755.
There was previously an earlier Baroque church on the site but the original church here dated back to 1147 when the forces of D. Afonso Henriques reconquered Lisbon from the Moors. On the main door there is a relief by Francisco Leal Garcia depicting king Afonso Henriques kneeling in thanks for his victory.
The current basilica was designed by Reinaldo Manuel dos Santos and the fairly restrained exterior hides a veritable explosion of Rococo splendour within. There is only a single nave, but this is still impressive enough.