The Bering Land Bridge is an important feature in understanding why various organisms are where they are on the planet. 10,000 years ago or so, when much of the earth's water was frozen on land during the ice age, there was less water in the oceans so more land was exposed. And this was the case all over the world. But in this one area, between what is now northeastern Asia and northwestern North America, it is significant because it was possible to travel on land between the two continents. Animals that had evolved on one side or the other were now able to intermingle and migrate much farther than they had before. In fact, this one small connection, that was before and is now under water, connected not just North America and Asia but Europe, South America and even Africa. Not that all animals crossed over but that it became possible to.

Image: Time lapse of the Bering Land Bridge.
Public domain photo by NOAA