Between 34000 and 30000 B.C, at the height of the ice Age much of world’s water was iced. Ice was appeared as vast continental ice sheets. Because of this the Bering Sea was hundreds of meters below than the current level. As a result there was a narrow land between Asia and North America .It was known as Beringia. Beringia is thought to have been some 1500 kilometers wide. A moist and treeless tundra, it was covered with grass and plant life, attracting the large animals that early humans hunted for their survival.
The firs people who reached North America almost certainly did so without knowing that they had crossed in to a new continent. They were only tracing animals and hunting as their ancestors did along the Siberian coast and then across the land bridge. For the first Americans It took thousands of years to reach the land what is now United States. Evidence of early life in North America have been found continuously. A hunting look-out was found in north Alaska and finely crafted sphere points and items found near Clovis, New Mexico Recently.
Similar artifacts that were found through the North and South America Proves that the life was probably already well-established in Western Hemisphere by some time prior to 10000 B.C. Mammoth was the principal source o food of the first people. But Mammoths began to die out and they hand to go for another source of food. Then they hunted Bison, Deer and other small animals as their food. Instead of meet plants, berries, and seeds became an increasingly important part of the early American diet. Early people had to increase their food sources so they started to cultivate. Native Americans in what is now in Central Mexico cultivated Corn, Squash, and beans. Slowly this knowledge of cultivation spread northwards.
Hohokams build ball courts and Pyramid-like mounds settled in which is now Phoenix, Arizona. Adenans were the first Native Americans to build mounds in what is now the United States. Earthen burial sites and fortifications were constructed by them around 600 B.C. Some mounds were in the shape of birds or serpents. Adenans were absorbed or displaced by various groups collectively known as Hopewellians. Hopewellians were great traders. Remain of several thousand of mounds in Ohio, proves that these people had a great culture.
By around 500 A.D., the Hopewellians were vanished and a new tribe known as Mississippians came to action. There are evidence that at this era Native Americans took slaves as workers and practiced human sacrifice. In what is now the south west United State, the Anasazi, ancestors of modern Hopi Indians build unique and apartment like structures using stone. The most famous creation is the “cliff palace” of Mesa Verde, Colorado. It had more than 200 Rooms. The discovering the America by Europeans is believed to be the most accurate reason for the destruction of Native Americans.