Anfang

The western side of Belka's southern coast is remarkably straight, with few exceptions. Anfang is very mountainous, with the highest peak in the northeast measuring about 1100 feet. In the waters to the west of the coast, there sleeps a once-mighty fleet, sunk by persistent air attacks from a battle nearly forgotten. A destroyed, abandoned airbase sits among the hills near the shore, with the wreckage of a battle long ago still scarring the once-beautiful landscape.

The Belkan War
It was here on June 20th, 1995 that the Mars, Mercury and Jupiter strike teams of Operation: Broom struck the Belkan forces in the last real battle of the war. Some brave Belkan pilots flew their aircraft through a tunnel to the airbase, only to be struck down by the Demon Lord upon their exit.

Sources

Ace Combat Zero: The Belkan War (the game)

Official Ace Combat Zero Website by "Project Aces" - http://www.acecombat.jp/ace-zero/top.htm