The United Mexican States (Spanish: About this sound Estados Unidos Mexicanos (help·info)), commonly known as Mexico (pronounced Listeni/ˈmɛksɨkoʊ/; Spanish: México [me.χi.ko] ( listen)), is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico. Covering almost 2 million square kilometres (over 760,000 sq mi), Mexico is the 5th largest country in the Americas by total area and the 13th largest independent nation in the world. With an estimated population of over 112 millions, it is the 11th most populous country and the most populous Spanish-speaking country. Mexico is a federation comprising thirty-one states and a Federal District, the capital city.
In Pre-Columbian Mesoamerica many cultures matured into advanced civilizations such as the Olmec, the Toltec, the Teotihuacan, the Zapotec, the Maya and the Aztec before the first contact with Europeans. In 1521, Spain conquered and colonized the territory from its base in México-Tenochtitlan, which was administered as the Viceroyalty of New Spain. This territory would eventually become Mexico as the colony independence was recognized in 1821. The post-independence period was characterized by economic instability, the Mexican–American War and territorial cession to the US, a civil war, two empires and a domestic dictatorship. The latter led to the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system. Elections held in July 2000 marked the first time that an opposition party won the presidency from the Institutional Revolutionary Party.
Mexico is both one of the world's largest economies and a regional power, and since 1994 the first Latin American member of the Organisation for Economic Co-operation and Development (OECD), and a firmly established upper-middle income country. Mexico is considered a newly industrialized country and an emerging power. It has the 13th largest nominal GDP and the 11th largest by purchasing power parity. The economy is strongly linked to those of its North American Free Trade Agreement (NAFTA) partners, especially the United States. Mexico ranks fifth in the world and first in the Americas by number of UNESCO World Heritage Sites with 31, and in 2007 was the 10th most visited country in the world with 21.4 million international arrivals