Mexico, officially the United Mexican States, is a country 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. Mexico covers 1,972,550 square kilometers, making it the world's 13th-largest country by area; with approximately 126,014,024 inhabitants, it is the 10th-most-populous country and has the most Spanish-speakers. Mexico is organized as a federation comprising 31 states and Mexico City, its capital and largest metropolis. Other major urban areas include Guadalajara, Monterrey, Puebla, Toluca, Tijuana, Ciudad Juárez, and León. Pre-Columbian Mexico traces its origins to 8,000 BC and is identified as one of the six cradles of civilization; it was home to many advanced Mesoamerican civilizations, most notably the Maya and the Aztecs. In 1521, the Spanish Empire conquered and colonized the region from its base in Mexico City, establishing the colony of New Spain.