The Golden Twenties brought rapid development and growth to Berlin. It became the third-largest municipality in the world after the Greater Berlin act. The city held leadership positions in science, the humanities, music, film, higher education, diplomacy, business, and military affairs.
To pay reparations, the government pumped enormous amounts of money into the economy, resulting in staggering inflation that destroyed middle-class savings. After the mid-decade, U.S. loans enabled the economy to expand again. Berlin became the most industrialized city on the continent during the mid-1920s. The Tempelhof Airport opened in 1923, and the S-Bahn was electrified from 1924 onwards. In addition, Berlin had the second-largest inland harbor in Germany; this infrastructure was essential to transport and feed the over 4 million Berliners who lived in the city in the 1920s.