The Igreja de Santo Antão is one of the most prominent buildings on Praça do Giraldo, built between 1557-1563 on commission from Cardinal Henry (later King Henry of Portugal). Architect Manuel Pires designed it in Manueline-Renaissance style with an imposing white facade. The interior houses three impressive 18th-century marble altars and valuable religious paintings. Entry is free, making it an ideal stop while exploring the main square. The church represents an important example of Counter-Reformation architecture in Portugal.