This is the highly irradiated remains of an NCR camp on the Long 15. When you enter this location, the first thing you will notice is the destruction caused by the warheads launched at the end of the quest The Apocalypse. The area is populated with irradiated heavy troopers and glowing ones, along with their former commanding officer; Colonel Royez in a ghoulified state as well. The camp consists of a small firing range, numerous ruined buildings, and several crashed Vertibirds, along with a small amount of high tech gun cases along the road to the Northwest. Ammunition boxes and NCR weapons are littered about the area.
ps3 Attempting to fast-travel to another area while in the Long 15 will cause the player to drop dead as soon as it finishes loading.
ps3 Sometimes with Rex as a companion, If you go up the slanted road he will go outside the map and will be unretrievable. To fix this go to a dismissal terminal at either Gun Runners or the Lucky 38 and dismiss all companions and then retrive him from the King again. Fast traveling also may work.
pc If the player uses cheats to unlock all map markers and proceeds to fast travel to the Long 15, all menu items in the pause menu will be greyed out even after traveling to other areas. This can be resolved by reverting to an older save.