For many of our readers this chapter covers what is essentially “home,” the United States of America and Canada. Though Mexico is geologically part of North America, it is culturally part of South and Central America and thus was covered in the previous chapter. Formerly it was believed that the earliest people to inhabit North America, those who came to be called Native Americans, crossed the Bering Strait about 11,500 years ago, but recent excavations throughout the Americas have called this belief into question. Indeed, excavations at Meadowcroft, Pennsylvania, 30 miles/50 km south of Pittsburgh, have uncovered evidence of human civilization dating back to between 12,000 and 15,000 years. It is now thought that migrations from Northeast Asia could have begun 30,000 to 50,000 years ago.