personally believe in the theory of bridge

The Bering Land Bridge theory hypothesizes that humanity made its way to the New World by way of exposed land between Siberia and Alaska. Learn about the theory and why most archaeologists think this is possible.
Siberia and Alaska - otherwise known as Beringia - used to be much bigger than they are today. Because so much water was in ice form during the last Ice Age, sea levels were much lower, and much more land was exposed. This is why most archaeologists believe Siberia and Alaska were not only bigger, but were also once connected by a strip of land known as the Bering Land Bridge.
This is significant because most archaeologists also believe this land bridge is how humans crossed from the Old World into the New World. However, humans probably didn't cross out of curiosity, but out of necessity. In other words, they were looking for food.

Bering Land Bridge

Beringia

During the Stone Age, humans were hunter-gatherers. They hunted animals and gathered herbs and other plants for food. Because so much of the world was pure ice, vegetation would have been hard to find, so humans would have relied on animals for most of their nutrition.
At the time, Beringia was an oasis from the constant sheets of ice that covered so much of the world. It supported plant life, which meant it could support animal life. If animals crossed from Siberia into Alaska in search of food, humans would have naturally followed. Humanity was nomadic by necessity.