Completed in 1757, the Colegio de San Jerónimo was used as a school by friars of the Merced order, but because it did not have royal authorization, it was taken over by Spain's Carlos III and, in 1765, designated for use as the Royal Customs House. Today it's a tranquil, mostly open-air, site in an excellent state of preservation.
The handsome cloister centers upon an octagonal fountain, an evocative setting for occasional dance and other cultural performances. Head upstairs for great photo angles of Volcán Agua through stone archways.