Porte de Mars is an ancient Roman triumphal arch in Reims, France. It dates from the third century AD, and was the widest arch in the Roman world .
The Arch is 32 metres long and 13 metres high. It was named after a nearby temple to Mars. The arch has many highly detailed carvings on its exterior and on the ceilings of its three passageways. Local folklore says that the inhabitants of Rheims built the arch in gratitude when the Romans brought major roads through their city. It served as a city gate until 1544. In 1817, the buildings around it were removed, bringing the arch into full view.1