Forerunner elevator

Throughout various Forerunner installations, there are elevators that the Forerunners added to allow a quick ascent or descent over a large vertical span. Like most Forerunner architecture, these elevators and their control panels have a tendency to be geometric. All three Halo games have Forerunner elevators.

Installation 04
All Forerunner elevators that appear throughout the series have no visible mechanical mechanism to move them (with the exception of the elevator in The Library). All of them were destroyed when John-117 detonated the Pillar of Autumn and destroyed the installation.

Forerunner elevators are first observed near Installation 04's Control Room. There are a few identical elevators, all of which are octagonal. The panel to control it has three components. It's left and right sides are irregular hexagons, and are also mirror images of each other. The center piece is a rectangle, and has a curving line down the middle.

In a Flood Research Facility, octagonal elevators appear again. But unlike the elevators seen in Assault on the Control Room (AotCR), the sides and angles are not all the same. The panel to control it is identical to that of the one in near the control room. In the installation's Library, it appears that the same elevator is used multiple times. Unlike the other elevators seen so far, it is a circle. It moves up the center of the Library. It does not have a control panel, as it is not controlled by the player. 343 Guilty Spark appears to be the controller, but this is merely an assumption.

Forerunner Gas Mine
Forerunner elevators appear in the level through out the gas mine. There is one elevator that takes the player from an upper level down to a hangar. It is has an octagonal shape, with two symmetrical control panels. One is placed on the right side of the entrance, the other on the front and center wall. An identical elevator is observed shortly after the Arbiter cut the stations cables.

A second, unique elevator appears almost immediately after the beginning of the level The Oracle. It drops down through a Flood Research Facility. It takes in large canisters, then stores them in breakable fixtures on the surface. It is symmetrical and completely geometric. It is not controlled by the player at all, but rather an unknown AI. This is the only observed rotating elevator. An elevator atop a spiraling walkway goes to an open area where three cables are that support the entire station. It is, like most Forerunner elevator, octagonal; all the sides and angles are contiguous. It's control panel is identical to that of the ones first seen in The Arbiter.

Delta Halo
On Delta Halo, a variety of elevators can be seen. The main elevators encountered are sea-elevators. They are capsules that are ejected downwards into the water, and then move along to their next destination.

Halo 3
No Forerunner elevators are seen in until the level The Covenant, and this is also the only level where Forerunner elevators appear in Halo 3. Two identical pentagonal elevators go up and down from the base of the Barrier Towers to a switch room where the towers can be  deactivated. Their control panels are circular with geometric details inside the circle. If you zoom in on the control panel, you can see the Marathon symbol.

At the end of the level The Covenant, Master Chief and The Arbiter take a similar shaped elevator up to Truth. While being of similar shape, the elevator has a similar structure to elevators seen in Halo:CE and Halo 2.