A most prominent landmark in the Tagus Estuary is the Forte do Bugio lighthouse strategically set approximately 2.5 kilometres offshore at the mouth of the river.
Its familiar circular silhouette at the confluence with the Atlantic Ocean is clearly visible all along Lisbon‘s riverside, as well as from high up on the city’s iconic 25 April suspension bridge.
The lighthouse stands proud on an oval-shaped platform in one of the choppier parts of the estuary where the ebbs and flows of the Atlantic currents are at their most treacherous.
Officially called the Fortaleza de São Lourenço da Cabeça Seca, its construction began in the early 17th century at a time of Spanish occupation during the period historically known as the Sixty Years of Captivity.
During the Spanish occupation, King Filipe I (1580-1598) commissioned the military engineer and Italian architect Giovanni Vicenzo Casale to improve the defensive system of the Tagus Estuary, which at the time was under constant threat of invasion by English and Dutch pirates.
The fortress was finally completed in 1657 in the prevailing Rennaissance style a year after the death of João IV, and the 46-metre-high lighthouse seen flashing every five seconds at night was added in 1775 after the original construction was washed away during the great earthquake of 1755.