The Chicxulub Crater was located in the Yucatán peninsula in Mexico.
According to Sarah Jane Smith, it was the result of a meteor impact that caused the extinction of the dinosaurs. According to the Fourth Doctor, however, the crater was caused by a Drak colony ship. (PROSE: The Dragons of Prague)
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While facing the Process, the Seventh Doctor recalled the tremendous impact created when "Adric hit Mexico," (PROSE: Cat's Cradle: Time's Crucible) suggesting that the Chicxulub crater was the result of the Briggs' freighter crash. (TV: Earthshock)