Anti-gravity gondola

Summary
The Forerunners created large gondolas that travel by utilizing anti-gravity technology to ferry individuals to and from long distances that are otherwise difficult to traverse. There are several iterations of the gondola found throughout the Halos, one of which uses anti-gravity "tethers" below and above it. The only way for a person to get to the Library of a Halo is through one of these or the use of a teleportation grid.