The Trier Amphitheater is an ancient Roman amphitheater located in Trier, Germany. It was built in the 2nd century AD, during the reign of Emperor Trajan. The amphitheater was used for gladiatorial games, animal fights, and other public spectacles.

The Trier Amphitheater is one of the largest Roman amphitheaters in the world, with a seating capacity of up to 20,000 people. The amphitheater measures approximately 120 meters long and 90 meters wide, and is surrounded by a high wall made of local sandstone. The arena itself measures about 70 meters long and 50 meters wide.

The amphitheater fell into disrepair in the Middle Ages, and much of its stone was used for other building projects in Trier. However, in the 19th century, efforts were made to restore the amphitheater to its former glory. Today, visitors can explore the ruins of the amphitheater, including the underground tunnels where animals and gladiators were kept before their fights. The site also offers great views of the city of Trier and the surrounding countryside.