The Porta nigra, which means "Black gate", considered to be the hallmark of Trier, and reported in the List of world heritage of humanity by UNESCO. Built in the year 180 in the heyday of the Roman Empire they are the oldest surviving fortification in Germany. The Trier of the time, also called "the Rome of the North", was surrounded by a high defensive wall with four gates. The only preserved and today are striking in their might and Majesty. Their width is 36 meters, height 30 meters and the depth is 21, 5 meters.

Despite its name Porta nigra was built of white stone, darkened by time. 7200 boulders unique structures, each weighing up to 6 tons, are joined without cement: a perfect fit they were joined by iron clamps and secured with liquid tin. During the middle ages for the sake of a precious metal these brackets are partially pulled through the holes. But, in spite of many wars and robberies, the construction of completely escaped.

A legend connects the safety of the Black gate with the hermit Simeon, who lived with them at 1028 1035 years, and was buried, according to his will, under the gate. After his death, to the Porta nigra was built a Church called the Church of Saint Simeon. By order of Napoleon in 1803, the Church was almost completely destroyed, and the gate acquired its original appearance. Today the Porta nigra is a Museum.