The Romans built Porta Nigra around 180 AD. While savoring its grandeur, you begin to appreciate why Trier claims to be Germany’s oldest city. Black Gate was one of four entrances to the fortified town. It is the sole survivor. The others were dismantled for building materials during the Middle Ages. Porta Nigra was reconstructed upon the orders of Napoléon Bonaparte in the early 19th century. The huge sandstone blocks without mortar stretch 75 feet wide and 90 feet tall.