Known more commonly as La Merced, this is one of Antigua’s most beautiful churches, painted in a bright yellow and adorned with white lily motifs on its columns. Inside are the ruins of its old monastery (5a Avenida Norte and 1a Calle Poniente, 9 a.m.–6:30 p.m., $0.50 admission) with the Fuente de Peces, said to be the largest in Latin America and interestingly in the shape of a water lily.
The pools were once used for breeding fish. The upper level affords some wonderful city views and the fountain just outside the church is also worth a look.