The sharpened shield

The Sharpened Shield is the forerunners equivilent of a bomb shelter. The shield was the UNSC military world named Onyx that housed a slipspace conduit that opened for a limited period of time when the Halos were activated. The portal was housed within the hallow core of the world onyx where a number of forerunner transportation pads led up to it. Within the portal was a Small sun contained within a large dome basically the instilation was a "bubble" that could hold billions if not trillions of people, unfortunatly due to reasons unknown the Forerunners failed to reach the shield in time and so were tragically wiped out. During the Battle of Onyx 12 spartans; 3 spartan 2's and 8 spartan 3's were trapped inside along with Docter Halsey and Chief Petty Officer Mendez.