system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do workers get the last crane off the top of a skyscraper when they finish building it?
gpt
The cranes that actually sit on the building itself? Well, there are two kinds of those.

So-called "skycranes" are actually lifted in via helicopter. Those will be removed in the same way.

But "internal climbers," which are located in the center of the building and "climb" up a few floors at a time on a hydraulic lift as the building is constructed? Well, when the final floor is finished, the crane will raise components to build a temporary scaffolding to support itself. This permits the removal of some of the very large components on which the crane usually rests, e.g., the hydraulic lift, steel beam supports, etc., which the crane lowers down to the ground out the outside of the building. Once that is finished, the rest of it is then disassembled and sent down the construction/freight elevator.