This is the perimeter around The Front Line Base. There are several look out turrets. The wall is 1200 meters which is almost 4,000 feet from the main building at it's center.

The wall is actually two, the first tunnels down into the earth 50 meters or 164 feet, so if anything decides to dig into the fortress they are well seen and prepared for before they get in. It reaches another 50 meters into the sky. It's made out of titanium metal with a rubber silicon reinforcement to give and way when anything hits it.

The second wall, the inner one, is almost identical but instead of 50 meters it's 75 meters the equivilant to 246 feet. The towers are posted on the inner and higher wall.