A handsome white-stuccoed colonial church a few blocks west of the Plaza de Armas, with twin bell towers and a richly carved wooden interior. Originally founded by the Mercedarian order in the early 1600s, the building has been rebuilt several times after earthquakes.
The interior altarpieces, particularly the side chapel of the Virgen de las Mercedes, are good examples of Andean colonial baroque. The square in front of the church is one of the quieter places in the centre to sit for a coffee.