maraf24
I have a local knowledge. This is informal, unmarked place for nudist. 
We don't tag such places, as it lacks verifiability. 
OSM isn't database for everything. Such place is a good example.
https://wiki.openstreetmap.org/wiki/Good_practice#Verifiability
https://wiki.openstreetmap.org/wiki/Good_practice#Don.27t_map_temporary_events_and_temporary_features