Sandbox

Sandbox is upcoming map that will be included in the Mythic Map Pack. It's name has lead many to think that it will be a similar map to Foundry. In certain Bungie.net forum posts, there have been repeated queries as to whether there will be a larger version of Foundry, and in some cases, Bungie staff or higher ranked members have replied and said that there was one in the works.

''*This map is expected to be released along with Assembly, Orbital, Citadel, Longshore, and Heretic in the Mythic Map Pack. "...in early 2009. “Winter,” as they say." -Lukems in the 10/10/08 weekly update.''

Otherwise, this map could be another map set in a desert location, like Sandtrap

Trivia

 * This map contains a hidden skull. Locating the skull earns the player the 'Sandbox Skull' achievement. The crest of the hidden skull on this level appears to be a likeness of the Monitor, furthering suspicions that this will be a forge-heavy map.
 * On Bungie's video designed for receiving the game of the year award on G-4's G-Phoria, the Bungie crew was seen standing in a strange new place. This zone was suspected to be Sandbox.
 * This map may be a more Heavy vehicular version of foundry.