Lisbon is home to Belém Tower, a fortified monument built on the Tagus River in the early 16th century.
King Manuel I commissioned the tower during Portugal’s Age of Discoveries. Construction began in 1514 under architect Diogo de Boitaca and was completed around 1520. Its original purpose was to defend the northern entrance to Lisbon’s harbor, working with another fortification on the opposite riverbank.
The tower combines late Gothic Manueline architecture with military features, including battlements, turrets, thick walls, and artillery positions. Decorative details include carved ropes, crosses, and armillary spheres associated with Portuguese maritime exploration.
Belém Tower is sometimes described as being in the middle of the river, but its position changed because of alterations to the shoreline and riverbed. It became a UNESCO World Heritage Site in 1983 together with the nearby Jerónimos Monastery.