Built to guard Lisbon in the 16th century, Belém Tower is now a UNESCO World Heritage Site. Jutting into the Tagus River in Belém, the exterior features ornate Manueline religious and maritime carvings. Climb to the top for city views.
Lisbon's Torre de Belém was completed in 1520 during Portugal's Golden Age of Discovery. In the centuries that followed it became a customs post, telegraph office, lighthouse and political prison.