Mexico is a federal republic in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost two million square kilometers (over 760,000 sq mi), Mexico is the sixth 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, Mexico is the eleventh most populous country and the most populous Spanish-speaking country in the world while being the second most populous country in Latin America. Mexico is a federation comprising 31 states and a federal district that is also its capital and most populous city. Other metropolises include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
Pre-Columbian Mexico was home to many advanced Mesoamerican civilizations, such as the Olmec, Toltec, Teotihuacan, Zapotec, Maya and 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. Three centuries later, this territory became Mexico following recognition in 1821 after the colony's Mexican War of Independence. The tumultuous post-independence period was characterized by economic instability and many political changes. The Mexican–American War (1846–48) led to the territorial cession of the extensive northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires and a domestic dictatorship occurred through the 19th century. The dictatorship was overthrown in the Mexican Revolution of 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system.