Do you know how the ice usually found on rivers and lakes differs from glacial ice? Do you know how massive glaciers formed and that they are capable of moving and advancing? It turns out that ice in a glacier is different from that which covers bodies of water in winter. Under the pressure of the upper layers, ice in glaciers becomes stratified and begins to "flow" because a slippery surface forms between the layers. That is how the massive glaciers of the last ice age, which began approximately 115,000–120,000 years ago, were able to cover the whole of Europe almost as far as the Mediterranean, and in America – even further south, reaching the confluence area of the Ohio and Mississippi rivers. There was enough moisture here for a glacier to form. In contrast, the climate in Siberia back then, just as it is now, was dry, so despite the low temperatures, a glacier did not form there.