> For the complete documentation index, see [llms.txt](https://alex-plugins.gitbook.io/ouranos/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alex-plugins.gitbook.io/ouranos/structures.md).

# Structures

Structures are building placed randomly into the world. They can contain NPCs or mobs.

### Adding custom structures

You can add custom structures to your world by adding them into the *structures\_custom* values in your world configuration. You must have first created them (see Customization [Structures](/ouranos/customization/structures.md)).

### Structure configuration

Each structure has its own configuration file located either in */Ouranos/structures/Ouranos/* folder for Ouranos structures and in */Ouranos/structures/* folder for Custom structures.