Mexico is a country in Central America, which had several thriving civilizations, including the Mayan and Aztec empires. Mexico City is the capital of Mexico and is the world's second most populated city. The city lies on the site of the old Aztec capital and sits below two high volcanoes, a position resulting in earthquakes. Mexicans are mestizos, of mixed European and Native Americans descent and the main language is Spanish. More than one-fifth of Mexicans work in agriculture growing crops such as Coffee, vegetables and fruits for export, whilst wheat, corn, and sugarcane, avocados, chilies and green peppers are homegrown to feed their families. Mexico's climate is ideal to grow citrus fruits. Sonoran Desert is one of the largest deserts in the world and the Pinacate National Park, west of Nogales desert is littered with some of the world's largest cacti, the giant saguaro, which can grow up to 60 feet tall.