EARLY AMERICA

Mesa Verde settlement in Colorado, 13th century. (© Russ Finley/Finley-Holiday Films)	Aerial view of the Great Serpent Mound in Adams County, Ohio, created by members of the Native-American Fort Ancient Culture (A.D. 1000-1550). (Mark C. Burnett/Photo Researchers, Inc.)
The Castillo de San Marcos, built by the Spanish 1672-1695 to guard St. Augustine, Florida, the first permanent European settlement in the continental United States. (© Miles Ertman/Masterfile )	Fountain and mission remains of the San Juan Capistrano Mission, California, founded by Spanish Franciscan missionaries led by Fray Junípero Serra in the 1770s. (© Chuck Place)

At the height of the most recent Ice Age, about 35,000 years ago, much of the world's water was locked up in vast continental ice sheets. A land bridge as much as 1,500 kilometers wide connected Asia and North America. By 12,000 years ago, humans were living throughout much of the Western Hemisphere.

The first Americans crossed the land bridge from Asia and were believed to have stayed in what is now Alaska for thousands of years. They then moved south into the land that was to become the United States. They settled along the Pacific Ocean in the Northwest, in the mountains and deserts of the Southwest, and along the Mississippi River in the Middle West.

These early groups are known as Hohokam, Adenans, Hopewellians, and Anasazi. They built villages and grew crops. Some built mounds of earth in the shapes of pyramids, birds, or serpents. Their life was closely tied to the land, and their society was clan-oriented and communal. Elements of the natural world played an essential part in their spiritual beliefs. Their culture was primarily oral, although some developed a type of hieroglyphics to preserve certain texts. Evidence shows that there was a good deal of trade among the groups but also that some of their relations were hostile.

For reasons not yet completely understood, these early groups disappeared over time and were replaced by other groups of Native Americans, including Hopi and Zuni, who flourished. By the time Europeans reached what is now the United States, about two million native people, maybe more, lived here.

The first Europeans to arrive in North America — at least the first for whom there is solid evidence — were Norse. They traveled west from Greenland, where Erik the Red had founded a settlement around the year 985. In 1001, his son Leif is thought to have explored the northeast coast of what is now Canada. Ruins of Norse houses dating from that time have been discovered at L'Anse-aux-Meadows in northern Newfoundland.

It would be almost 500 more years before other Europeans reached North America and another 100 years after that before permanent settlements were established. The first explorers were searching for a sea passage to Asia. Others — chiefly British, Dutch, French, and Spanish — came later to claim the lands and riches of what they called the "New World."

The first and most famous of these explorers was Christopher Columbus of Genoa. His trips were financed by Queen Isabella of Spain. Columbus landed on islands in the Caribbean Sea in 1492, but he never saw the mainland of the future United States. John Cabot of Venice came five years later on a mission for the king of England. His journey was quickly forgotten, but it provided the basis for British claims to North America.

The 1500s were the age of Spanish exploration in the Americas. Juan Ponce de León landed in what is now Florida in 1513. Hernando De Soto reached Florida in 1539 and continued as far as the Mississippi River. In 1540, Francisco Vázquez de Coronado set out north from Mexico, which Spain had conquered in 1522, in search of the mythical Seven Cities of Cibola. He never found them, but his travels took him as far as the Grand Canyon in Arizona, as well as into the Great Plains.

While the Spanish were pushing up from the south, the northern portion of the present-day United States was slowly being revealed through the journeys of other Europeans. These included Giovanni da Verrazano, Jacques Cartier, and Amerigo Vespucci, for whom the continent — America — would be named.

The first permanent European settlement in what was to become the United States was established by the Spanish in the middle 1500s at St. Augustine in Florida. However, it would not play a part in the formation of the new nation. That story took place in settlements farther north along the Atlantic coast — in Virginia, Massachusetts, New York, and the 10 other areas colonized by a growing tide of immigrants from Europe.