When Did We Get Here?

For as long as I've been on the planet, we've been taught that humans reached the American continents some 10,000 years ago from Asia across the Bering Straight. The South American part of that is now being challenged by ongoing field work currently  being done in Brazil.

Stone tools have been found at a Brazilian rock-shelter may date back as far as 22,000 years ago.  This article on the Science News website discusses the controversial evidence found at various sites and the work being done to find out exactly when humans reached this hemisphere.