Circa 65 million BC, Briggs' freighter crashed into Mexico's surface (PROSE: Cat's Cradle: Time's Crucible) with Adric on board, killing him and causing the extinction of the dinosaurs. (TV: Earthshock)
Circa the 15th century, the First Doctor, Susan, Ian Chesterton and Barbara Wright visited what would become Mexico. Barbara attempted, and failed, to alter the history of the Aztecs. (TV: The Aztecs)
In 1941, during the Day of the Dead, psychotic artist Susini attempted to create sculptures from the flesh and bone of living humans. Her plot was defeated by the Eighth Doctor and local artists Frida Kahlo and Diego Rivera. (COMIC: The Way of All Flesh)
The Torchwood Institute was aware that a small time rift was present in Mexico. (COMIC: Shrouded) Following his encounter with Torchwood Three, Captain John Hart left to reside in Mexico. (TV: Exit Wounds)
In the 2010s, the Mexico border was among the places where newly-hatched Zygons were settled across the world as part of Operation Double, resulting in a minority of Zygons residing in New Mexico under the pretence of being British migrants. (TV: The Zygon Invasion)
Notable individuals' ties to Mexico
Behind the scenes
Cybus Industries website
Cybus Industries had a tie-in website, no longer hosted by the BBC as of July 2013.
The website had a collection of the CEO of Cybus Industries, John Lumic's, thoughts. He mentioned that living in an airship had its "disadvantages", such as a if a dissident Cybus executive "accidentally" fell into the Grand Canyon, which in Pete's World was in the United States of Mexico, then they couldn't vote against Lumic again. Lumic corrected himself by saying, "I'm sorry, did I say disadvantages? I meant to say advantages."
The website featured an interview with Lumic. When asked what the "best" decision he made was, Lumic answered with, "Assassinating the Prime Minister of the United States of Mexico".