In 1953 the Ministry for Public Works set up a committee, the purpose of which was to study the technical and financial feasibility of the construction of a bridge over the Tagus River in Lisbon.

On April 27, 1959 a public tender was launched for the construction of a bridge between Alcântara and Almada equipped with an upper deck for road transport and a lower deck for rail transport. But later the Portuguese authorities decided to construct the bridge only for road transport and to prepare the bridge for subsequent rail transport. The deck would however be installed in a second phase.

On May 9, 1962, the project was awarded to the leading company of the Consortium, the United States Steel International (New York), Inc.

Therefore, the construction of the bridge and road accesses started on the 5th November 1962.

The Suspended bridge project was created by the New York Engineering Office, Steinman, Boynton, Gronquist & London and the Gabinete da Ponte sobre o Tejo and National Civil Engineering Laboratory.

For the study, launch, operation and inspection of the construction of the Bridge, a Department from the Ministry for Public Works called the Office for the Bridge over the Tagus (Gabinete da Ponte sobre o Tejo) was set up.

With the completion of the work widening the road transport deck, the installation of the rail transport deck and the structural reinforcement the railway crossing on the lower deck and the six road lanes were opened in 1999 (November 1998).

Since then, 25 April Bridge has been the road and rail connection between both banks of the river Tagus in Lisbon.

With a central span of over one kilometer and a total length of 2.3 km it is one of the longest suspended bridges in the world.