1920s
The 1920s decade covers the period from 1920-1929.

This decade on Earth is set between the First and Second World Wars. During that time, the  is a popular dance. Some women are referred to as flappers. () The United States economy starts to deteriorate, an event which causes the Great Depression and has consequences even in an alternate timeline (see 1929). (; ) During the Prohibition era, organized crime rises to never-seen heights. The book Chicago Mobs of the Twenties chronicles this era, and serves as a guide for the civilization on Sigma Iotia II. ()

Scientific breakthroughs on Earth include the launch of the first liquid propellant rocket. ( okudagram) Radio becomes a popular form of entertainment during this decade. () In art, the film Metropolis is released and Irving Berlin writes the song "Blue Skies". (; ) The song "Someone to Watch Over Me" is also released. ()

Years 

de:1920er
es:Década del 1920
fr:20ème siècle#Années 1920
it:Anni 1920
nl:1920s
pt:Década de 1920
sv:1920-talet