Officially the United Mexican States is a federal 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 two million square kilometres (over 760,000 sq.mi.), Mexico is the fifth largest country in the Americas by total area and the 13th largest independent nation in the world. With an estimated population of over 120 million,it is the eleventh most populous and the most populous Spanish-speaking country in the world and the second most populous country in Latin America. Mexico is a federation comprising thirty-one states and a Federal District, its capital and largest city.
Pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, the Toltec, the Teotihuacan, the Zapotec, the Maya and the Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its base in Mexico-Tenochtitlan, which was administered as the Viceroyalty of New Spain. This territory would eventually become Mexico following recognition of the colony's independence in 1821. The tumultuous post-independence period was characterized by economic instability, the Mexican-American War that led to the territorial cession to the United States, the Pastry War, the Franco-Mexican War, 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.
Mexico has one of the world's largest and most diversified economies, with an abundance of natural resources such as oil and silver. It has the fifteenth largest nominal GDP and the eleventh largest GDP by purchasing power parity. The Mexican economy is strongly linked to those of its North American Free Trade Agreement (NAFTA) partners, especially the United States. Mexico ranks first in the Americas and sixth in the world by number of UNESCO World Heritage Sites, and in 2010 was the tenth most visited country in the world, with 22.5 million international arrivals annually.