National Geographic Kids!: http://kids.nationalgeographic.com/kids/places/find/mexico/
Fact Monster: http://www.factmonster.com/ipka/A0107779.html
Brittanica Kids: http://kids.britannica.com/elementary/article-345743/Mexico?#9345743.toc
CIA World Fact Book: https://www.cia.gov/library/publications/the-world-factbook/geos/mx.html