The Casa de Cortés, on the north side of Plaza Hidalgo, is where conquistador Cortés established Mexico’s first municipal seat during the siege of Tenochtitlán, and later had the defeated emperor Cuauhtémoc tortured to make him divulge the location of Aztec treasure (the scene is depicted on a mural inside the chapel). Contrary to a plaque on display, and popular belief, Cortés never actually resided here.
Today it's where people come to register their marriage.