The terrans built two Gauntlets, effectively military training grounds. The first was lost when the zerg overran it, prompting the creation of a second "in a sector of space much harder for the swarms to overrun". This is an in-joke by Blizzard Entertainment staff, responding to criticisms that the original version of the map favored the zerg too highly.
1998-10-23. The New Gauntlet. StarCraft Compendium Map Archives.