Porta Nigra

Porta Nigra is a historic landmark and the largest Roman city gate in Germany, located in Trier. Constructed around 180 AD and supposedly used by the Roman Emperor Constantine the Great, it is one of the few great Roman architectural structures still standing in Germany. Porta Nigra (Latin for 'Black Gate') owes its unique dark color to the covering of it with a thick layer of sandstone in the 12th century. After being badly damaged by French revolutionaries in 1793, the gate was partially restored in the middle of the 19th century. It has served various functions, from a military outpost, to a temporary exhibition hall, before being declared a World Heritage Site by UNESCO in 1986. Visitors today can explore the remaining four towers, which provide fantastic views of the surrounding area, as well as an interior entrance hall with a 15th–century fresco. It is open daily from sunrise to sunset and has a small admission fee.