Unable to answer "What kind of memorial is this?" – Ernst Thälmann Denkmal (Memorial) – https://osm.org/node/5609381469 via StreetComplete 58.0:

Site of a bust depicting Ernst Thälmann, lost since 1989. No type of memorial as suggested by StreetComplete fits. Part of the larger area, which was used as memorial site in ideological use in the GDR called Ehrenhain. More context in photos.

Attached photo(s):
https://westnordost.de/p/219682.jpg
https://westnordost.de/p/219683.jpg