=> What is the structure

You don’t actually know. You’ve been up there hunting for new kinds of computer parts, and the technology there seems to be… significantly advanced. There are also writings in some ancient language. You have managed to guess that whoever made this is looking for something. Perhaps, they have already found it?

The whole thing gets above the ash cloud layer. That is terrifying.

Regardless, it has been taken over by all sorts of creatures. You can see them flying around. It is dangerous.