My imagination has long been "enthused" by the "Mammoth Bone dwellings"
of Central Europe from c 15000 years ago ("some of the oldest shelters known to have been constructed by pre-historic man"
) Mainly Ukraine but also Russia and Moldova so still relevant to your subject I feel in representing a type of site significantly "hidden" from Western knowledge/access over the years and hence under-valued. Geographically they are located on the "Russian Plain". The most famous is at Mezhirich Ukraine (But see also - Mezin, Gontzy and Yudinovo - the latter is in Russia). This Web site has some photos of the excavated site, reconstructions etc at Mezhirich http://donsmaps.com/mammothcamp.html
Another significant type of archaeological site from the area is that of "Mesolithic Burial Grounds"
from 10th to 7th millennium BC e.g Oleneostrovski Mogilnik in Russian Karelia and Vasilievka in Ukraine. These demonstrate the development of society in post glacial Europe http://deepblue.lib.umich.edu/bitstream/handle/2027.42/24870/0000297.pdf?sequence=1
Neither type is represented as far as I can see on any T List?? Nor do they figure in the list of Archaeological sites in the wondermondo link?