The existing wall was built between 1374 and 1378, making it over 600 years old. It is 12 meters high, 18 meters wide at the base and 15 meters wide at the top. It has four gates: Changle Gate in the east, Anding Gate in the west, Yongning Gate in the south and Anyuan Gate in the north. Xi'an's City Wall is one of the oldest and best preserved city walls in China and one of the largest ancient military defensive systems in the world.