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 The water level change within the Caspian Sea is an indirect reason for which plants may not get established. These affect aquatic plants of the Volga Delta, such as "Aldrovanda vesiculosa" and the native "Nelumbo caspica". About 11 plant species are found in the Samur River Delta, including the unique liana forests that date back to the Tertiary period. Reptiles native to the region include spur-thighed tortoise ("Testudo graeca buxtoni") and Horsfield's tortoise. The history of the Caspian sea is divided into two parts: a Miocene stage, determined by tectonic events that correlate with the closing of the Tethys Sea,