Lisbon's Belem Tower was built from 1515 to 1520 and once served as a watchtower for Lisbon when it stood in the middle of the Tagus River. Today the river has changed its course and the Belem Tower sits on the river bank. The Belem Tower serves as Lisbon's symbol of the Age of Discovery, often serving as a symbol of the country. UNESCO has listed the Belem Tower in Lisbon as a World Heritage monument.

