The Dome has three significant features: three oil silos, the massive spherical tank with catwalks throughout, and two small metal sheds on the ground. Each silo has its own staircase to the top, where there are usually several Barrels of varying types. The staircases and tops of the silos are somewhat guarded by sheets of metal and sandbag barricades. Underneath The Dome, many more barrels of loot and oil can be found. The vast majority of the loot to be found, however, is within and on top of the Dome itself by way of a lengthy and often dangerous path of catwalks and pipes that snake up the sides of the main spherical tank.
To climb the tank, start on the opposite side of the silos and climb up the large pipe in the ground. After that, the path is very self-explanatory. There are three main layers to the tank, and to access each one, you must climb out of the tank and around the outside.
The first layer is a catwalk with guard rails that cuts through the center of the tank. In the middle, the catwalk forks into a circular area, and then leads to the other side of the tank, where a downward ramp leads to the bottom of the tank (This ramp usually has, at most, a single crate or barrel at the end of it).
The end of the first catwalk leads outside to the next stage of jumps and climbing, which then leads to the second catwalk. This one is nearly identical to the first, save for the hardest jump to make in the entire journey. You have to sprint-jump onto a small beam to proceed.
The path then leads to another ramp up, which will take you to the third level at the top of the tank.
The safest descent from the top of the tank is simply back down the way you came, though the thin pipes that encircle the dome allow players to find other ways down to ground level. Regardless of your approach to descending, there is a small shortcut at the exit of the first set of internal catwalks by way of a hanging platform above one of the external oil silos. Falling or jumping down onto this platform always deals damage, so beware using this shortcut if you are at low health.
There is a way to jump off the side of the main tank without taking any damage, as if you must jump from the top to between the two giant pipes, and crouching while moving backwards as you fall will negate all damage.
Infrascructure The Dome offers access to two Oil Refineries, which can be found inside the two small metal sheds located around the tank's base. The surplus of Crude Oil that can be found in the many red Barrels around the monument allows easy access to quick production of Low Grade Fuel.
The Dome is a useful area for players at earlier stages in the game, as its radiation levels are much lower than monuments like the Power Plant or the Launch Site.
While the area under the Dome is ripe with Barrels, the path that leads up and inside the main tank yields up to 6 Basic Crates if you're willing to make some extra jumps. If not, it appears as though up to 2 crates can spawn at each circular area on the internal catwalks. On top of the Dome, 4 Military Crates can be found, which carry the highest-quality loot besides the Elite Crate that the monument has to offer.