Yongning Gate, commonly known as the South Gate, is the South Gate of the city wall of Xi'an Ming Dynasty. It is also the oldest and longest-standing one in the city gate of Xi'an. Nowadays, Yongning Gate is the traffic around the island. There is Nanmen Square outside, Nan Avenue inside and Nanguan Main Street outside. Yongning Gate is the most complete and beautiful one rebuilt among the gates of Xi'an City Wall. The newly completed underground passage enables visitors to enter it safely. The arrow tower on the city was destroyed in the Xi'an Defense War (also known as the two tigers guarding Chang'an). Yongning Gate has been repeatedly damaged and rebuilt, witnessing the vicissitudes of Xi'an City. When Erhu guarded Chang'an, in order to defeat the enemy, the reinforcements had to shoot and shell the city wall and destroy the gate buildings such as Yongning Gate (South Gate) Archery Tower.