Akua

Akua is one of the best defensive facility locations in the game, due to its high altitude and the surrounding geography. The mountains east of Akua are so tall and steep as to be completely impassible by anything (air or ground vehicles or ground troops). There is a sheer cliff dropoff (the crater, or caldera, wall) to Akua's west.

Enemy air vehicles are limited to about a 290 degree sector of attack, versus the typical 360 degrees, and can only come in low due to altitude restrictions. Plus, the surrounding terrain is excellent for anti-aircraft defense.

Ground forces can only approach Akua via two roads - one to the north, the other to the south. Both are long, uphill approaches and both are narrow canyons, making them ideal for mine-laying and defense in-general.

There is also no tower adjacent to Akua, and the difficult ground approach and lack of hiding places make it hard to get an AMS close to the base.