Torre de Belém

Belém Tower officially the Tower of Saint Vincent is a 16th-century fortification located in Lisbon that served as a point of embarkation and disembarkation for Portuguese explorers and as a ceremonial gateway to Lisbon. It was built during the height of the Portuguese Renaissance, and is a prominent example of the Portuguese Manueline style, but it also incorporates hints of other architectural styles. The structure was built from lioz limestone and is composed of a bastion and a 30-metre four-storey tower. (Wikipedia)