Officially the United Mexican States, Mexico located in North America. It is bounded by three seas, the Pacific Ocean to the south and west, the Caribbean Sea to the south east and the Gulf of Mexico to the east. The history of Mexico goes back to a number of ancient civilizations, the best known of which are the Mayans and Aztecs. Mexico City is one of the many modern cities that are home to numerous ancient monuments. Mexico is also one of only 18 megadiverse countries in the world making it flora and fauna of particular interest to visitors.