Overview
It was first given this designation in The Official Handbook of the Marvel Universe - Alternate Universes 2005. The name is derived from the cover date of the first story set in this reality, Marvel Super-Heroes v1 #18 (January 1969). Earth-691 has been separate from the Earth-616 timeline since at least 1901, and possibly as early as the 1810s.
This Earth is also notable for being invaded by Martians from H.G. Wells' novel The War of the Worlds in the year 2001, during which, nearly all of Earth's heroes were killed or driven off the world. The last superhero to remain on Earth was Spider-Man who was eventually killed and his remains preserved by a Martian scientist.
While there is a Dargo in this reality, it has not been established whether he is the same one that has appeared in the Thor and Thor Corps stories.
At the climax of the Wisdom limited series, the Martians of Earth-691 invade the Britain of Earth-616 in order to kill that world's Jonathan Raven while he was still a child. They create a portal using the mind of his mother Maureen Raven, who was a member of MI: 13.
In Marvel Zombies 5 #3, Machine Man, Howard The Duck from Earth-616, and Jacali Kane, (Daughter of "Hurricane" Kane and Apache Little Cloud from Earth-483) arrive in Florida on November 2020, looking for new strains of the Zombie Plague. The heroes do not find any new zombie samples, but team up with Killraven, and (after the standard confused hero on hero fight then team-up) use the Zombie Plague to create an outbreak so bad that the aliens all retreat back to Mars. Killraven shouts that the zombies saved Earth, and Machine Man, Howard, and Jacali move on to the next dimension, possibly still leaving a zombie outbreak behind them.
Read more about this topic: Earth 691