The shape of the land, depth of the oceans and their names which we know today will often not be the same our ancestors knew. Geographical changes have occurred and continue to occur due to the movement of the earth’s plates and the amount of ice in the world. Today there is great concern on the impact of melting ice on the world due to global warming. When our ancestors where travelling great ice sheets covered North America and Northern Europe creating a fall in sea levels. This led to the exposure of sea floors resulting in the creation of land bridges and shallow seas. Some examples are;

• The Bering Straits used to have a land bridge allowing people to cross from northern Asia, the area now known as eastern Siberia in Russia into North America, to the area now known as Alaska, USA.
• Australia used to be connected to New Guinea and Tasmania and the seas were shallow making it easier for people to travel between these lands
• The largest island within the Isles of Pretani known today as Great Britain was originally connected to mainland Europe. That connecting land is referred to today as Doggerland.