Black Sea–Caspian Steppe language and the Northeast Caucasian languages are related to Hurrian and Urartian. This implies that the mountaineers of the Caucasus have been in their present location for a very long time. According to the most common theory the Indo-European languages originated on the steppes north of the Caucasus and Black Sea. Some time before 3000 BC the Maikop culture appeared in Circassia and Kabardia. It is noted for its excellent gold and silver work. North on the steppe was the Yamnaya culture which was probably Indo-European. Around 1000 BC there was a bronze-age Koban culture in the Kabardian area which
Caspian Sea human settlements. The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a