What does "national monument" mean?

A man-made structure, site, or natural feature that is designated as important to a country's heritage or national identity and is protected as such.

National monument

Common synonyms include: aniakchak, cultural landmark, federally designated, heritage site, historic landmark, historic monument.

noun

noun ·Rare ·Advanced level

Noun

1
A man-made structure, site, or natural feature that is designated as important to a country's heritage or national identity and is protected as such.
2
memorial consisting of a structure or natural landmark of historic interest; set aside by national government for preservation and public enjoyment wordnet