Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Built Environment (hierarchy name)
4. Single Built Works (hierarchy name)
5. single built works (built environment)
6. [single built works by specific type]
7. [single built works by function]
8. military buildings
9. military security buildings

Anotations

Scope note:

Fortification chambers mostly below ground level built of reinforced concrete or similar material and usually provided with embrasures; also, dugouts that are reinforced (as with logs or bags of sand) and usually have firing slits.