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. fortifications (built environment)

Anotations

Scope note:

Small defensive fortifications used as a gun emplacement or observation point; used in battle situations and routinely to command control of a site. Examples are pillboxes made of concrete that were used in battlefield defensive systems during World War I.