Portugals unique ability,Casa Da Índia ,significantly increases the yields of International Trade Routes, but limits those routes to cities on the coast or with a Harbor. This ability also grants Trader units additional range and the ability to embark on water tiles as soon as theyre unlocked. Includes the Portugal civilization with João III, the Nau unique unit, and two unique structures, the Navigation School building and the Feitoria. Joao Joaos unique ability isPorta Do Cerco ,which grants all units increased Sight. It also increases Trade Route capacity whenever Portugal meets a new civ and provides Open Borders with all city-states. Portugals unique unit, the Nau, is a naval melee unit that replaces the Caravel. It starts with one free Promotion, requires less maintenance than the Caravel, and has two charges to build Feitorias, special shipping ports unique to Portugal. Unique Infrastructure Portugals unique building, the Navigation School , replaces the Universit