Unus Annus is Latin, and means "One year" in English.
"Memento Mori," the channel's tag line, is Latin and is best translated as "Remember you will die."
The series ran from November 15th 2019 to November 14th 2020.
Many of the episodes where Mark and Ethan participate in new activities were found on Airbnb Experiences. This is fact is stated by Mark and Ethan in the episodes Mark and Ethan Go on a "Drum Date" (2020) and Becoming the World's Greatest DJs (2020), and others.
The unofficial theme song for Unus Annus is the song "Turncoat" by Michael Rothery. The song gained massive popularity after people recollected on the memories of Unus Annus by listening to this song.