A natural monument is a natural or natural/cultural feature of outstanding or unique value because of its inherent rarity, representative of aesthetic qualities or cultural significance. Wikipedia

Natural or natural/cultural feature of outstanding or unique value Wikidata

A natural/cultural feature which is of outstanding or unique value because of its inherent rarity, representative of aesthetic qualities or cultural significance. Guidance for selection of a natural monument is: a) The area should contain one or more features of outstanding significance OmegaWiki