Mexico is the northernmost country of Latin America. It lies south of the United States, and the Rio Grande River separates the two countries. The history is truly colorful. Mexico was home to the Aztec Indians who built large cities, developed a calendar, a counting system, and used a form of writing. The Aztec empire fell to the Spaniards in 1521. Besides the Indians and the Spanish, a third group of people developed in Mexico, called mestizos. These people, who had both Indian and white ancestors (mostly Spaniards) are of the majority in Mexico and take great pride in their Indian ancestry. Mexico has a wide selection of landscapes and climates. Mountains and high plateaus take up more than two-thirds of Mexico. Mexico has six major land regions: (1) the Pacific Northwest, which is generally dry, mostly desert, (2) the Plateau of Mexico, the largest land region. It has a series of active volcanoes which extend across Mexico at the plateau's southern edge, (3) the Gulf Coastal Plain, is covered with tangled forests of low, thorny bushes and trees, (4) The Southern Uplands which consist of steep gorges cut by mountain streams, (5) the Chiapas Highlands, contain large block-like mountains that rise over nine thousand feet, (6) the Yucatán Peninsula, a low limestone plateau with no rivers. More than eighty-five percent of the people belong to the Roman Catholic Church. Mexico began printing stamps in 1856, but few stamps of Mary were published as can be seen in the short list shown below. The reason for this meager harvest lies in the strong anti-catholic and anti-clerical character of most of the Mexican governments during the twentieth century. The World Book Encyclopedia, World Book, Inc., Chicago, 2000, pgs. 448-463.