Foundry

Foundry (Originally coded "Art Vandalay," by Bungie during production) is a multiplayer map released for Halo 3 as part of the downloadable Heroic Map Pack. It was made available on December 11th, 2007. It was made exclusively for Forge, as almost all features of the map can be changed, deleted, or even replaced by any object that Forge has allowed.

Description
There is no set description, for Foundry, as it can be Forged into almost any configuration imaginable. Essentially, Foundry is an abandoned warehouse filled with equipment and empty container boxes. The default configuration of Foundry is a mostly close-quarters, two level map with a few long hallways. The power weapons are distributed into the corners and center of the map. The Rocket Launcher is in the center on the second level, there are Brute Shots in each base, and Sniper Rifles are in the corners opposite the bases.

There are 2 cranes, on this map, as well as two shipping areas: A and B. Most of the boxes have "P425" printed on them, indicating possibly that that section of Foundry is Section P425, or it could be a serial number of some sort. It could also be referring to some destination for the boxes.

Getting Out Of Foundry
To get out of Foundry you first must be in Forge. This is much easier if everything is deleted before hand. Become a monitor and fly into one of the windows, while holding forward and slightly up you will slowly move up the window. You will stop underneath a small ledge; continue holding the control stick and create a respawn point. If you followed the instructions correctly, you will see your respawn point outside through the window. You can then commit suicide and respawn out of the map. Once outside of the map you can create teleporters and move around outside of the map. Another way to get out is to create a single box and a crate on top. Then make a turret facing into the room as close to the window as possible. Then look directly up while on the turret and turn into forge mode. Another way to get out is to put a box on the ground and make it spawn later into the game. Wait there until the box spawns in. When it does spawn in it will push you under the level. Then, turn into the monitor before you fall too far. Falling to far will cause death and you will need to repeat the process again. another method is to make a bridge float near the same window and place a machine gun turret on top of the bridge near the window. Then you can jump onto the machine gun turret, look all the way up, turn into the monitor and you're out. Somewhere along the lines, you should skim the garbage piles and see a cutout of a chef, unmistakably similar to the "Chef Boyardee".

Be warned, many places you step outside of the map will cause you to either be killed by the Guardians or fall to your death.

Strategies
Note: These strategies are for the default Foundry map variant.
 * The forklifts and the trucks can be blown up, and with them an attacker.
 * The chain link fences can be shot though offering a great way to shoot the fusion coils.
 * Go for the Rocket Launcher in this map.
 * Due to the fact that there is a Grav Lift that spawns by default on the original Foundry, it is possible to kill people with Scenery quite easily; such as throwing one underneath a Wire Spool and then fooling someone to step into it.
 * Sometimes you can get splatters in this map if your grenade's explosion force kicks a Wire Spool into the air and it hits someone.
 * You can crouch jump out of the windows in the small room of each base. This is extremely useful if you are holding the Oddball, and your defense gets overwhelmed, and you need a quick way out. The crouch jump needs to be precise, or you can get stuck in the window.

Forge

 * Using boxes, it helps to accentuate the natural "U" shape to the level it will allow it to stay balanced.
 * It is possible to push a teleporter into the space above the crane nearest to the base area. Doing this will create a great weapon storage space. You can also shoot through the invisible floor at that area.
 * It is possible to push a box into the ground, to do this you need to brace each side of the box with walls, put 1, or 2 doors in it and grab the box it should go in to the ground a bit, let go of the box and push the doors in a bit deeper and repeat the process, do this as many times as you want to add a bit of originality to your map.

Trivia

 * In the trash found on the floor, there is a blue draft notice paper and a pack of cigarettes. In a different pile of trash, there is a purple hippo that is hard to see without aid from the Sniper Rifle.
 * FACTORY CPLX 09 is located on the edge of a lake; opposite the lake there is another factory. If you escape from the "foundry" building and zoom-in on the factory, you should see the words, "FACTORY CPLX 71" on the side.
 * The geographical feature behind factory complex 71 is a crudely drawn Mount Kilimanjaro seen from the wrong side, or it has at least the same profile. Voi is West South-West of Kilimanjaro, while in Foundry the mountain is rotated so that it is viewed from the south. The mountain has no snow, is too small and too close to Voi.
 * A Red vs Blue D.I.Y. video was presented using this map.
 * Although some assumed this factory was the one presented in the short Arms Race this is not true as the assembly line in Arms Race is Misriah Armory located on Mars, and Foundry is clearly located on Earth.
 * It is possible to fall to your death on this map. You must be in Forge to do this. Place a double box anywhere flat on the ground, then set it to spawn at start: no. Then start a new round. Then go and crouch where you placed the box. When it appears, you will not be able to get out of crouch. Simply move any direction, and you will fall below the map to your death. This can be useful to make "death teleporters" where you place a receiver node under the map and a sender node inside.
 * Art Vandelay, Foundry's codename, is George Costanza's alias in the TV sitcom "Seinfeld". Bungie probably gave that name because Art Vandelay is into architecture, and anything in this map can be made.
 * Foundry's Forge scenery inventory is impressive - however, it lacks a large amount of items from original maps, such as nearly 50% of High Ground's Scenery (Tire, Telephones, etc.) as well as things like Supply Cases and Comm Nodes (Snowbound).
 * Unknown to many, there is a large cargo shaft above one of the "inlets". A similar hard-to-see shaft is also in the Blue base in Rat's Nest.
 * The description refers to the New Mombasa Space Elevator, which was destroyed before the Halo 3 storyline begins.
 * A poster of the Forge Soccer Ball can be seen pinned up inside one of the chain link fenced off areas with the words "It Glows" underneath it.
 * In random piles of trash there are chinese boxes with Trogdor the Burninator on it.