In the 1930s, the Portuguese Government decided to replace the
Campo Internacional de Aterragem, at
Alverca, with two new airports nearer to Lisbon's city center: today's
Lisbon Portela Airport and the Cabo Ruivo Seaplane Base on the Tagus River, which handled transatlantic flights operated with seaplanes. Pan Am established its provisional seaplane base in Cabo Ruivo in 1938, at the southeast edge of today's
Parque das Nações. In 1942, the Portuguese Government decided to create a proper air-marine base, initially intended to be located on the same site. Eventually, it was decided to build the airport structures around the
Doca dos Olivais., two miles further up the Tagus. Avenida de Berlim, a major road, was built to connect the land and sea airports. The US intercontinental airline
Pan American World Airways, which was a major promoter of the airport's construction, used the airport During
World War II, the transatlantic clippers provided an escape route for refugees from Continental Europe, taking advantage of
Portugal's neutral stance in the war. With the enormous increase in the importance of terrestrial air traffic the era of seaplanes ended and the flight operations in Cabo Ruivo were discontinued in the late 1950s. The dock was redeveloped in the context of Lisbon's
1998 World Expo. Today, the dock is at the center of the
Parque das Nações, where the
Lisbon Oceanarium is located. ==Accidents and incidents==