Vladimir Ilyich Lenin (April 22, 1870 - January 21, 1924) was a human who lived during the 19th and 20th centuries on Earth. Lenin was the driving force behind the Russian Revolution in the early part of the 20th century. This revolution transformed Russia from a monarchy into a communist state, giving rise to the Soviet Union on Earth, which lasted from 1917 to 1991.
Lenin died in 1924. After his death, a power struggle broke out among the leaders of the Russian leadership, most notably between Joseph Stalin and Leon Trotsky. Lenin's remains were entombed in a mausoleum in Moscow. Gary Seven was captured during a mission at Lenin's tomb.
In an alternate timeline created by the Na'kuhl, one of the factions in the Temporal Cold War who originated in the 29th century, Lenin was assassinated in 1916. The assassin was never caught and bystanders claimed that he disappeared into thin air. No one was able to take Lenin's place and Russia never became a communist state. As a result, Russia was in disarray by the late 1930s and Adolf Hitler was able to instead focus on the west during World War II. After Hitler conquered Europe, he was able to invade and occupy the eastern United States. Captain Jonathan Archer and the crew of the Enterprise (NX-01) from 2154 were able to stop the Na'Kuhl and restore the timeline to its original state. (ENT episode: "Storm Front")