The Puerta de la Ciudadela is the only surviving piece of the colonial military wall that once surrounded Montevideo. Built in 1741, it formed the main entrance to the walled city from the landward side. The rest of the fortification was systematically demolished in the early 19th century as the city grew; the gate survived by accident.
The arch stands at the western edge of Plaza Independencia, framing the view down the pedestrian street into the Ciudad Vieja. It's modest in scale but carries a lot of history — you walk through the only piece of colonial Montevideo that remained above ground. The carved stonework on the keystone and the stonework are original.