The Torre de Belém was built between 1514 and 1519 as a gun platform covering the mouth of Lisbon's harbour. Its architect, Francisco de Arruda, then covered that piece of military engineering with decoration no other fortress in Europe carried: twisted rope carved in stone, ribbed domes on the corner turrets, and armillary spheres. Under one corner turret he set a rhinoceros head, generally counted as the first sculpture of the animal in western European art. It was probably modelled on the live rhinoceros King Manuel shipped to the Pope in 1515. The stone is Lioz limestone, which goes from white to honey depending on the hour.
The story everyone tells about it is wrong. The tower is usually said to have stood in mid-river until the earthquake shifted the Tagus, but it was built on a small island close to the north bank, and it is the shoreline that moved: reclamation and silting brought the land out to meet it. Inside, a tight spiral stair climbs through the governor's rooms and a powder store to an open terrace where a loggia frames the estuary. Below, at low water, the rock the tower stands on is still visible.