To: Land Shark who wrote (123185 ) 5/14/2008 11:13:33 AM From: one_less Respond to of 173976 During the thousands of years of native inhabitation on the continent, cultures changed and shifted. Archaeologists often name different cultural groups they discover after the site where they are first found. One of the oldest cultures yet found is the Clovis culture of modern New Mexico. A more recent example is the group of related cultures called the Mound builders (e.g. the Fort Walton Culture), found in the Mississippi river valley. They flourished from 3000 BCE to the 1500s CE. The ruins of Palenque.The more southern cultural groups of North America were responsible for the domestication of many common crops now used around the world, such as tomatoes and squash. Perhaps most importantly they domesticated one of the world's major staples, maize (corn). As a result of the development of agriculture in the south, many important cultural advances were made there. For example, the Maya civilization developed a writing system, built huge pyramids, had a complex calendar, and developed the concept of zero 500 years before anyone in the Old World. The Mayan culture was still present when the Spanish arrived in Central America, but political dominance in the area had shifted to the Aztec Empire further north. Upon the arrival of the Europeans in the "New World", native peoples found their culture changed drastically. As such, their affiliation with political and cultural groups changed as well, several linguistic groups went extinct, and others changed quite quickly. The name and cultures that Europeans recorded for the natives were not necessarily the same as the ones they had used a few generations before, or the ones in use today. The End of the Cold War and the beginning of the era of sustained economic expansion coincided during the 1990s. On January 1, 1994 Canada, Mexico and the United States signed the North American Free Trade Agreement, creating the world's largest free trade area. In 2000, Vicente Fox became the first non-PRI candidate to win the Mexican presidency in over 70 years. The optimism of the 1990s was shattered by the 9/11 attacks of 2001 on the United States, which prompted military intervention in Afghanistan, which also involved Canada. Canada did not support the United State’s later move to invade Iraq, however.