The ships and caravels of the Portuguese discoveries departed from the Tagus estuary. The wave that struck Portugal on the day of the 1755 earthquake rose up the river and flooded Lisbon and other locations on the bank.
In Lisbon, the Tagus estuary is crossed by two bridges. The oldest is the 25 de Abril Bridge (opened in 1966), one of the largest suspension bridges in Europe, which links the capital of Portugal to Almada.
The other is the Vasco da Gama Bridge, about 17 km long. It was inaugurated in 1998 and connects Lisbon (Sacavém) to Alcochete, Moita and Montijo. The widest part of this river is called Mar da Palha, a lake, and it lies between Lisbon, Vila Franca de Xira and Benavente.
At the entrance to the Tagus estuary there is a fortress (Forte de São Julião da Barra).
Every year in the port of Lisbon, hundreds of luxury liners dock, mainly at the Alcântara dock. In its estuary there is an ecological reserve (Natural Reserve of the Tagus Estuary, based in Alcochete) where several species of birds nest. Due to the great pollution of the river, there are no longer any dolphins permanently, but in recent years, during the summer, specimens have appeared, which after a good fishing trip return to the sea.