The Dom Luís I Bridge is a double-deck metal arch bridge that spans the River Douro between the cities of Porto and Vila Nova de Gaia in Portugal. At its construction, its 172 metres span was the longest of its type in the world.
Construction took place between 1881 and 1886 with the bridge being built adjacent to an existing bridge which it replaced. The granite pillars of the original bridge are still in place, standing on the Ribeira like a pair of gate posts.
One of the notable features of the Ponte Dom Luís I is it's two levels; one on top of the arch and the other suspended below it. Both decks were initially intended to carry road traffic but these days the top carries the Porto Metro trains as well as having a pedestrian walkway. It is worth making the crossing on the upper level.
Today Luis I Bridge is part of the UNESCO World Heritage Site of Historic Centre of Oporto, Luiz I Bridge and Monastery of Serra do Pilar.
The Citadelle of Quebec is an active military installation and official residence of both the Canadian monarch and the Governor General of Canada. It is located atop Cap Diamant, adjoining the Plains of Abraham in Quebec City. The citadel is the oldest military building in Canada, and forms part of the fortifications of Quebec City, which is one of only two cities in North America still surrounded by fortifications, the other being Campeche, Mexico.
The first fortifications in Quebec were built by the Governor General of New France Louis de Buade, and completed just in time for the Battle of Quebec in 1690.
After the British conquest in the second half of the 18th century, the problem of Quebec City's defences grew more acute.