Isolation

Isolation is a multiplayer map featured in Halo 3 that takes place at a Flood containment facility. The environment is a small, isolated bio-bubble that has contained the Flood on the Ark. The Milky Way galaxy hangs in the sky. The top level is grassy and untainted, but in the underground caves there is an obvious Flood contamination.

Topside
Isolation has a round, almost oval shape to it. It is a symmetrical map that consists of two levels: above and below. The upper level is a grassy hilltop with Forerunner architechure woven into the terrain. To the north, at the crest of the hill, lies a silver-gray multi-level Forerunner structure. A Battle Rifle spawns at either side of this tower. It can be used either for shelter (underneath, where the Shotgun spawns) or as a sniper perch (by standing on top). Directly behind this sniper perch is an escape chute that provides quick, one-way access to Isolation's bowels. From here, the player can go to his left (east), right (west), or move forward (to the south); you (probably) cannot regain entry to the sniper perch by going back up the chute.

Underground
Going left or right will lead to one of the cave's side entrances. At either entrance is a mancannon, which will blast you back to the top of the map. Going south will take you toward the mouth of the cave. Midway through the cave, there is a concrete bunker on either side. The bunkers have portholes for weapons fire. The bunkers can't be entered here. A little further south is where the Rocket Launcher and Ghost spawn. At the southernmost end of the cave, a thin rock ridge extends upward around the map's wall. This makes for another excellent sniper spot. Directly above the mouth of the cave is another Forerunner structure in the shape of an archway, which is rusted-brown. There is another drop-down here, which will put you near the Ghost/Rockets.

Bunkers
On the east and west sides of the map, near each of the two Man Cannons, is an entrance to the respective bases. A Regenerator exists in the main pylon of each base, as well as a Battle Rifle, Spike Grenades, and a Brute Spiker. You can either take a ramp down, or drop in from a hole above. Just above this area is the Brute Shot, a Battle Rifle, Fragmentation Grenades, and a Mongoose.

Tactics and Tips

 * Rushing for the Ghost and Rocket launcher at the beginning. However, also camping beside either of the 2 and waiting for others to ambush as they attempt to attempt to pick them up is also a good tactic if used well.
 * If sniping is your preferred tactic, taking the Sniper Rifle and staying on the outermost edges of the map helps to prevent you from being flanked. A regenerator with BR is usually good backup. But make a few kills then move position, people will start hunting you.
 * Entering the lower levels through the "chute" is a good escape tactic. While being chased, strategically throwing grenades toward the exit of the chute can kill or wound any would-be pursuers.
 * In the lower levels, there are the many "spore pods" that act like Fusion Coils; use them accordingly.
 * While going down the escape chute, you can grab a ledge inside it and camp. But be careful of grenades coming down the chute.

Discovery
Isolation is a map first referenced in the Halo 3 Beta code, and later appeared in a leaked photo of the list of Halo 3 maps. Most recently, IGN made an article describing it as a medium sized map, taking place in an enclosed, grassy area.

Trivia

 * If you look at the wall of Isolation then the wall on the Valhalla map you can see that the two look similar to one another, which could mean that Valhalla and Isolation are near each other.
 * Sentinels and Constructors can be seen flying above the map and can be shot at and destroyed, however difficult it is.
 * The Flood Growth Pods on the walls of the cavern do not contain Flood Infection Forms like those in the Flood Infested High Charity. When popped, they scream or moan, rather than spew Infection Forms, but they do cause damage to anyone unfortunate enough to stand next to them when they are set off.
 * In an interview, IGN asked Tyson Green if "there's an interesting thing that happens when you play Isolation for a while..." in which he responded "There is, but I don't want to spoil it." Many speculated that Flood would eventually spawn in the level. It has since been revealed that Flood Pods form in the upper areas of the map and the grass seems to die, though it does take a while for this to occur.
 * There is a ghostly face that can be seen when standing at the Ghost spawn and looking upwards.
 * Many players tend to band with each other during Infection matches in one of the bases room's in the Lower Levels. This is most likely because the room of each base is easily defendable due to the narrow hallway which one must get through.
 * It is very easy to fall to your death by simply attempting to fly out in a Banshee or a Hornet.
 * There have been many sightings of the Ghosts of Halo on this map.
 * It is easily possible to stand on the trees when being propelled by the lifts.
 * There is a Porta in the flood area. it can be accessed from the structure in the middle against the wall, where a player can unexpectedly or purposely drop in.
 * Isolation is so far the only Halo 3 multiplayer map to contain any form of the Flood.
 * The textures for Isolation's grass change as time goes by. You can observe this by taking "before and after" snapshots.
 * This is the only map in Halo 3 that does not include explosive materials that can damage you by default.
 * If you are on Isolation, if you use a Spartan Laser to destroy all the Flood Growth Pods, occasional Spartan Laser impacts can be seen near your position. The shots have no trail and seem to spontaneously occur and have no source. This could possibly be another ghost sighting.