The borough of Xochimilco was created in 1928, when the federal government reorganized the Federal District of Mexico City into sixteen boroughs. The Xochimilco borough was centered on what was the city of Xochimilco, which had been an independent settlement from the pre-Hispanic period to the 20th century. The area's historic separation from Mexico City proper remains in its culture. While officially part of the city, its identity is more like a suburb. This historic center was designated as a "Barrio Mágico" by the city in 2011. The borough is center-south of the historic center of Mexico City, and bordered by the boroughs of Tlalpan, Coyoacán, Tláhuac and Milpa Alta. It extends over , accounting for 8.4% of the Federal District's territory. It is the third largest borough, after Tlalpan, and Milpa Alta. The borough has an emblem, also known as an "Aztec glyph", which is a representation of the area's spongy soil from which two flowering plants emerge. In spite of the serious environmental issues, 77.9% of the territory is designated as ecological reserve, 15.2% as residential and 4.6 as commercial and industrial.