This is a radar image of the southwest portion of the buried Chicxulub impact crater in the Yucatan Peninsula, Mexico. The radar image was acquired on orbit 81 of space shuttle Endeavour on April 14, 1994.
It is this impact crater that has been linked to a major biological catastrophe where more than 50 percent of the Earth's species, including the dinosaurs, became extinct. The 180- to 300-kilometer-diameter (110- to 180-mile) crater is buried by 300 to 1,000 meters (1,000 to 3,000 feet) of limestone.