The Porta Nigra is a well-preserved Roman city gate located in Trier, Germany. Built around 180 AD, it served as a main entrance to the city and is a prime example of Roman architecture. The gate is made of large sandstone blocks and features impressive towers and arches. Today, the Porta Nigra is a UNESCO World Heritage Site, attracting many visitors each year. It reflects the historical significance of Trier, which was once an important Roman settlement known as Augusta Treverorum. The structure showcases the engineering skills of the Romans and their influence on urban design.