How did humans reach America after the last ice age?

It is generally thought that humans arrived in North America during the last Ice Age, toward its end. Much of Earth's water was in the form of ice, in glaciers that were a kilometer high and more, which resulted in the sea level dropping by a few hundred feet. This caused much of the seabed to become exposed in the form of dry land. There was what has been called a 'land bridge' across the Bering Straight, between Russia and Alaska, It wasn't really a bridge. It was dry land, the former seabed which had become exposed. Humans simply migrated across the so-called 'land bridge' from Asia into North America on foot. It is widely believed that there was an unglaciated corridor, through which humans could have passed to reach what is now the US. This theory does have its critics. Many suggest that pre-historic humans could just as easily have come to the Americas by water craft. It is generally believed that pre-historic humans had the ability to navigate significant distances at sea. The Bering Straight is only about 50 miles wide at its narrowest point. Some even suggest that South Sea Islanders could have travelled thousands of miles across the sea to reach South America. The truth, however, may never be known.