Lisbon (Portuguese: Lisboa), Portugal, the capital and largest city of the nation. It is situated on the north bank of the Tagus River estuary in southwestern Portugal, nine miles (14 km) from the Atlantic Ocean. At Lisbon, the estuary narrows and forms a natural harbor.

Lisbon has four principal districts. Alfama, the oldest district, is built on the slopes of a steep hill crowned by an old castle in the southeasternmost part of the city. On lower ground to the west is the Cidade Baixa district, which was largely rebuilt after much of the city was destroyed by an earthquake in 1775. Commercial docks lie to the west of Cidade Baixa in the district of Alcântara. Lisbon has expanded northward, and it is in the northwestern district of Bairro Alto that the city's most modern construction can be seen.

The city is not only the governmental but also the financial and commercial center of the country. A large number of exports and imports pass through its harbor. Local industry consists of the manufacture of textiles, pottery, chemicals, and petroleum and metal products. Tourism is another important source of income.

Lisbon is connected by rail and highway with the interior of the country and the rest of Europe. In 1966 a suspension bridge crossing the Tagus River was completed. Lisbon's Portela Airport is a major international air terminal.

There are many beautiful buildings, squares, and monuments in Lisbon. Notable are the Monastery of the Jerónimos, built to commemorate Vasco da Gama's discovery of a sea route to India; the Castle of Saint George, the oldest parts of which date back to the 9th-12th centuries; and Praca do Comércio, popularly known as Black Horse Square, which contains an equestrian statue of King Joseph I (reigned 1755-77) and is surrounded on three sides by government buildings.

Lisbon plays an important role in the country's cultural life. There are many museums in the city. Among the major ones are the Museum of Ancient Art, the Museum of Decorative Arts, and the Gulbenkian Museum. Lisbon is also the home of several symphony orchestras. Chief of Lisbon's institutions of higher learning is the University of Lisbon, founded in 1290.

Lisbon's site was visited by Phoenicians, and later occupied by the Romans and Visigoths. The Moors held Lisbon from 716 to 1147, and Spain held the city from 1580 to 1640. The earthquake of 1775 took the lives of some 40,000 to 50,000 persons. After a long decline in trade, Lisbon resumed importance as a port in the 20th century. Lisbon hosted a world's fair in 1998 dedicated to education about the oceans.

Population: 559,248.