From Halopedia, the Halo wiki
Sanctuary is a multiplayer map in Halo 2. It is set in a complex of Forerunner ruins, similar to those in the campaign level Delta Halo. Sanctuary was remade as Asylum in Halo: Reach and as Shrine in Halo 2: Anniversary.
One data set acquired by the UNSC Coral Sea was the peculiar site dubbed ‘Sanctuary.’ In addition to advanced Forerunner architecture, Delta Halo also housed a number of stone ruins. Some have speculated these are not Forerunner structures, but were instead transported here for other species that were temporarily housed on the ring. The layout of the site indicates its purpose was more cultural than practical; possibly a memorial or cenotaph. As a bright alien star illuminates these temple grounds, its peaceful lawns and elegant structures present a perfect picture against a backdrop of beautiful waterfalls and aqueducts. The walled grotto that defines the center point of this habitat would be a quiet and solitary place for meditation were it not for the contrasting cor currently afflicting the immediate surroundings.
Sanctuary is a symmetrical map, making it ideal for Slayer, Territories, and CTF gamemodes. Both bases contain the battle rifle, a turret, and a flag spawnpoint to the rear of each base. A walkway connects each base with a smaller structure that contains the sniper rifle. Under the structures is a tunnel that holds the shotgun and can provide a good escape route if you're overrun by the opposing team. Under the walkway that connects the bases and the structures is where the Warthog spawns. The center building connects to the smaller structures via two more elevated walkways that spawn plasma pistols and two ramps that lead to the side of the map that each hold a Covenant carbine. The center building spawns the map's only energy sword above the pond on the bottom floor.
Being set on Installation 05, the architecture is similar to the structures seen in the campaign. Sanctuary features an aqueduct system that feeds into the pond in the center. Waterfalls are also seen feeding into the pond that surrounds the Blue base, while the pond around Red base is dry. Large boulders and ruined pieces of the structures litter the open areas of the map.