Walking down the streets of a great city like Berlin, you don’t really know what lies behind the fancy facades. Often, the front of a building hides courtyard after courtyard of a graffiti-laced world where people live in simple apartments that date back to the 19th century, built to house the workers needed to power Berlin’s Industrial Age boom. Until recently, these apartment flats were “squats,” where people with little money camped out after the fall of communism. Today they are slowly gentrifying. Their very existence invigorates my favorite Berlin neighborhood, Prenzlauer Berg, with a trendy nonconformity and creative energy.