Alcaldía de San Juan (San Juan City Hall)

The building took nearly two centuries to finish — construction ran from 1604 to 1789, with additions continuing after that. The current façade, facing the Plaza de Armas and modeled on the Casa de la Panadería in Madrid's Plaza Mayor, was completed in 1840, designed by architect Pedro García. Inside the Sala Capitular, Puerto Rico's abolition of slavery was signed in 1873. The building still functions as the seat of municipal government, which is the point — it was never preserved as a relic. It remained in use.