Original: The act increased the area of Berlin 13-fold from 66 km ² ( 25.5 mi ² ) to 883 km ² ( 341 mi ² ) and the population doubled from approximately 1.9 million to near 4 million , with almost 1.2 million of these new inhabitants coming from the 7 surrounding towns alone .
Simplified: Its area went from to and the population doubled from approximately 1.9 million to near 4 million , with almost 1.2 million of these new inhabitants coming from the 7 surrounding towns alone .