Sandbox

Sandbox is a map that is included in the Mythic Map Pack. It was stated by Bungie to be the "ultimate Forge map". Sandbox was first released along with the Halo Wars: Limited Edition, and it is unknown when Sandbox and the other two Mythic Maps come to the marketplace.

Introduction
Sandbox's setting and architecture are similar to Sandtrap, but its forging capabilities greatly surpass Foundry. The map consists of three distinctive layers: the main ground area best for vehicle-based maps, the "Sky Bubble", a location high above that can be used to create floating maps with falling death barriers, and "The Crypt" underneath which is the best way for making enclosed arenas. The layers are separated by default, but can be accessed and connected in Forge.

Sandbox, along with the other two Mythic maps, Assembly and Orbital were shipped with the Limited Edition of Halo Wars. Bungie has confirmed they are working to get these maps available on Marketplace as soon as possible after Halo Wars' release. The release date for the other three Mythic maps is unknown, although it is confirmed that they will be released with Halo 3: ODST in fall.

Setting
Sandbox is set in the midst of a barren desert surrounded by many rolling sand dunes, similar to Sandtrap. Large Forerunner towers can be seen in the distance. Bungie hinted that, similar to Sandtrap, the Covenant may have also conducted archaeological excavations here. The map is based at sunset, with a ringed gas giant in the sky, and a setting sun on the horizon.

It has been confirmed that Sandbox's watchtower has the ability to seek out and destroy players and Forge items if they move outside Sandbox. If the player moves outside of the barrier, the watchtowers will shoot out lasers which will instantly destroy them, even if they are inside a vehicle (allthough these watchtowers can be blocked off in forge).

Default Sandbox
The default Sandbox is perfectly symmetrical, and considered by Bungie to be a medium-large map. It contains two bases opposite each other, with cover laid in between. The map's vehicular arsenal includes a Chopper, Warthog and two Mongooses for each team. The infantry has Rocket Launchers and Missile Pods to counter them, and an Overshield is located on top of a pillar in the center of the map.

The structures are similar to Sandtrap's, being constructed of weathered rock and other similar materials. The surrounding terrain is composed of sand dunes, with large Forerunner walls in the distance. In Forge, the default Sandbox has a grid to help line up objects.

Sky Bubble
The Sky Bubble is essentially an area in Sandbox that can be reached via built-in teleporter in forge, so you can play on both the normal map and the Sky Bubble at the same time. It is located high above Sandbox's ground level, and has another grid system to help line up objects.

The Sky Bubble is circular and 3 times larger than the ground area of the default Sandbox. The tops of the watchtowers from the ground floor are higher than the "ground" of the Sky Bubble; they cast light over the area. When the player falls off the edge of objects he or she has placed, there is a death barrier between the Sky Bubble and the ground below, so maps like Guardian and Ascension could be accurately remade.

The Crypt
The Crypt is a large, enclosed area located under Sandbox. It can be accessed by removing the block shaped structure in the center of the map and dropping down the shaft, which is very long and dark. The area of the Crypt is on the same scale as the main area of Foundry; it is suitable for Grifball without any Forging. The floor is square-shaped and the height is the same as the width. The blue grid also appears down in the crypt.

The Crypt has a very high ceiling, and the walls seem to be constructed of black stone. There are lights in the walls that emit an eerie glow in the area. Since the Crypt can be accessed via teleporter and the shaft, it will be possible to play in the Crypt, the ground level, and the Sky Bubble in one map.

The Crypt is 32X32 grid squares. Approximately 16X16 single walls.

Forge
""Sandbox combines large-scale vehicular combat with a limitless amount of Forge customization. Boasting a tiered, open-world layout, “Halo 3” players will be able to build their own unique game experiences using the Forge map editor. Sandbox is a map unlike any Bungie has ever created.""

- Bungie.net

The center of the main level of Sandbox is a flat, empty floor, similar to Foundry but visually resembling Sandtrap. The map is built from Forge-editable blocks, pillars and ramps. The map includes "just about every kind of building block you could ever want", for example tunnels, crouch-only doorways and quarter-pyramids; see here for a full list. The item limits have been loosened: for example, unlike Foundry's 20 wall limit, in Sandbox it is possible to place 40 walls. Sandbox supports every vehicle in Halo 3 Multiplayer except the Elephant.

A new Forge item included in Sandbox is an orb of light that colors its surroundings in either red or blue; it can be used to differentiate the two bases, similar to most maps made by Bungie. Another is the "Kill Ball", a large orange sphere that kills anyone who comes into contact with it; a total of four are placeable. Another new addition is a golf club that acts like a Gravity Hammer and ball along with a cup to hit it in. Like the soccer ball, it is purely for aesthetic purposes and in no way will score you a point. In Forge mode, a blue-grid appears on the map to help the player place objects the way they want it, with accuracy and precision.

The Grid only appears in Forge, not in actual gameplay modes such as Slayer, Capture the Flag, or Infection. There are many new items to be placed in Forge. These are mostly Sandtrap-themed (as well as Ghost Town-themed wooden objects), to keep within the style of the map. All full list of Sandbox objects is located here.

Skull
Sandbox features a hidden skull known as the Sandbox Skull. This skull, if obtained, unlocks the Sandbox Skull Achievement and 25 gamerscore. The crest of the hidden skull on this level appears to be a likeness of the Monitor. The skull is located slightly to the right of the sunset between two sand dunes at the edge of the large ring that encircles the map. It can be reached by planting a Reciever, or Two Way Node at its location in Forge, or by building a tunnel of tube pieces across the level to get there safely.

Trivia

 * When looking at an empty heatmap, it somewhat resembles the orginal Xbox.
 * The Guardians on Sandbox work similar to those on Snowbound. In this case though once you leave the map all towers shoot a laser at you.  Each one is an instant kill and will continue to shoot you until you respawn. It is also similar to the guardians on Sandtrap because a Sentinel Beam is also fired from the towers. The difference is that the Sentinel Beams on Sandtrap are not meant to kill you rather they were meant to trigger the mines when you are in the minefield. Also, upon further inspection, the beams are actually just orange-colored gauss shots.
 * Technically, Sandbox was the first Mythic Map to be revealed to the public. The two settings for Bungie's acceptance speech videos were in the "Sky Bubble" and "Crypt" areas of Sandbox.
 * The default vehicles on map, which are the Mongooses, Warthogs and Choppers at each base, are the same as Sandtrap, with the only difference being 2 less Warthogs.
 * After Blackout, it is the second map to be set in the dark, though the lights emanating from the pillars in the distance negate it. It is also the third map with a setting sun, behind Standoff and Ghost Town.
 * On the IGN interview with Dan Miller, he stated that Sandbox could be considered the biggest map in the game, but this may be because of the extra area the "Sky Bubble" and "Crypt" occupy. It is also likely to be the tallest map in the trilogy due to its tiered design.
 * This map is the spiritual successor to two previous Halo maps: Foundry, and Sandtrap. Sandtrap because of aesthetics, and Foundry because of the massive and unlimited amounts of Forge possibilities.
 * Sandbox provides very versatile Forge items that will greatly reduce the need for the interlocking Forge technique.
 * The Crypt was used in Red vs Blue: Relocated Part 3 and Part 4 as a setting for Sarge's underground Lab and Simulation room.
 * With the endless possibilities in designing maps, it's possible to remake almost any of the maps from the previous Halo games such as, Boarding Action (Level) and Longest (Level).
 * The planet in the sky is a blue-green, ringed gas giant. This suggests that Sandbox is set on a moon.
 * If the player overloads Sandbox using Trip Mines in Forge, the grid will disappear and the Sentinel towers will not fire at the player if he or she goes out of bounds, thus enabling the player to explore the level freely. Unfortunately, this might also cause the skull to disappear, and if the player enters the Sky Bubble, since the grid is gone, the game will act as if there is nothing between the Sky Bubble and the ground floor; thus causing all items to fall onto the ground. However, the death barrier is still present, and without the grid, it is much more difficult to know where it is. However, it is possible that the grids will remain even if you overload the map, but the towers won't shoot you, allowing you to easily obtain the skull.
 * If the player got to one of the towers around the map in pan-cam mode there is a symbol quite similar to the splatter medal, but it's actually someone on fire as opposed to being run over.
 * The stakes that surround Sandbox are almost exactly alike to the ones that surround Sandtrap. The only notable differences are that Sandbox's stakes glow much more brightly when a player approaches them, and that they also emit a beeping noise.
 * The Grifball gametype in the playlist Team Mythic is played in "The Crypt", although it has been aptly renamed the "Grifbox".
 * The picture titled "fool with a view" that Luke Smith drew for a weekly update led many people to believe that Sandbox was a remake of Sandtrap at night.