The Yucatán Peninsula (, also , ; ) is a large peninsula in southeast Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north and west of the peninsula from the Caribbean Sea to the east. The Yucatán Channel, between the northeastern corner of the peninsula and Cuba, connects the two bodies of water. The peninsula is approximately in area. It has low relief, and is almost entirely composed of porous limestone. The peninsula lies east of the Isthmus of Tehuantepec, the narrowest point in Mexico separating the Atlantic Ocean, including the Gulf of Mexico and Caribbean Sea, from the Pacific Ocean. Some consider the isthmus to be the geographic boundary between Central America and the rest of North America, placing the peninsula in Central America. Politically all of Mexico, including the Yucatán, is generally considered part of North America, while Guatemala and Belize are considered part of Central America. Etymology The proper derivation of the word Yucatán is widely debated. 17th century Franciscan historian Diego López de Cogolludo offers two theories in particular. In the first one, Francisco Hernández de Córdoba, having first arrived to the peninsula in 1517, inquired the name of a certain settlement and the response in Yucatec Mayan was "I don't understand", which sounded like yucatán to the Spaniards. There are many possibilities of what the natives could have actually said, among which "mathan cauyi athán", "tectecán", "ma'anaatik ka t'ann" and "ci u t'ann". This origin story was first told by Hernán Cortés in his letters to Charles V. Later 16th century historians Motolinia and Francisco López de Gómara also repeat this version. In some versions the expedition is not the one captained by Córdoba but instead the one a year later captained by Juan de Grijalva. The second major theory is that the name is in some way related to the yuca crop, as written by Bernal Díaz del Castillo. Others theories claim that it is a derivative of Chontal Tabascan word yokat'an meaning speaker of the Yoko ochoco language, or an incorrect Nahuatl term yokatlan as supposedly "place of richness" (yohcāuh cannot be paired with tlán). History Pre-human The Yucatán Peninsula is the site of the Chicxulub crater impact, which was created 66 million years ago by an asteroid of about 10 to 15 kilometers (6 to 9 miles) in diameter