The Berlin Wall was not one wall but two - 155 kilometers of concrete and wire encircling West Berlin completely, cutting it off from East Germany. The barriers stood four meters high, separated by a 'death strip' under constant surveillance by armed guards authorized to shoot anyone attempting escape. Between 1949 and 1961, some 2.5 million East Germans had fled westward, a hemorrhage of skilled workers and professionals that threatened to destroy the East German economy. The wall was the brutal solution: seal the border, trap the population, turn a city into a prison.

For 28 years, families lived separated by concrete. The wall ran through streets, through apartment buildings, through the heart of a capital that had been unified for centuries. Checkpoint Charlie became famous as a crossing point for foreigners; for Germans, it was a reminder of what they couldn't cross. The wall fell in hours; the division it created lasted decades longer. Even now, the line where the wall stood runs visibly through Berlin's texture - cobblestones set in pavement marking the path of something no longer there but impossible to forget.

Before the wall, there was ruin. Allied bombers flew 310 raids on Berlin during World War II, dropping over 67,000 tons of bombs. By war's end, 50,000 Berliners had been killed and every building in the city was damaged. In the central districts of Mitte and Kreuzberg, up to 90% of structures were destroyed. The city lost 300,000 houses. Only 29 of its 234 hospitals survived.

What remained became politically contested rubble. The original Berlin Palace, a baroque masterpiece dating to 1443, survived the bombing damaged but repairable. The East German government demolished it anyway in 1950, claiming the site for socialist mass demonstrations. The Reichstag, seat of parliament since 1894, stood half-ruined for decades while vegetables grew in its shadow. The Nazi buildings that hadn't been bombed were deliberately destroyed - nobody wanted to preserve the 'most feared address in Germany.' Berlin was rebuilt four times in a century: by emperors, by Nazis, by occupying powers on both sides of a Cold War. The city you see today is an archaeological site of ideologies.

German reunification formally occurred on October 3, 1990, but reuniting Berlin took longer. Between 1990 and 2000, approximately 1.5 trillion euros was transferred from West to East Germany for reconstruction and economic support. The disparities persist: eastern Berlin still shows higher unemployment, lower wages, different voting patterns than the western half. The wall came down in days; the division it created will take generations to heal.

The architectural evidence of division remains everywhere. East Berlin has its Soviet-style apartment blocks, its Karl-Marx-Allee parade boulevard, its reconstructed buildings following socialist ideals. West Berlin has its modernist towers, its consumer culture, its deliberate contrast to everything across the wall. Where they meet, the seams show. The Reichstag was rebuilt with a transparent glass dome - a symbol of democratic openness atop a building that had seen empire, republic, dictatorship, and division. Whether the symbol matches the reality is a question Berlin keeps asking itself.

The Monday demonstrations in Leipzig that helped bring down the wall drew their power from an old slogan: 'Wir sind das Volk' - 'We are the people.' As reunification approached, the chant shifted: 'Wir sind ein Volk' - 'We are one people.' This transformation from protest to unity happened in weeks, driven by crowds who sensed that history had cracked open and could be pushed through.

Berlin has always been a city of movements. The Weimar Republic's fevered creativity, the Nazi horror, the Cold War standoff, the techno clubs that colonized abandoned buildings after the wall fell - each era brought people who saw Berlin as a place where the normal rules might not apply. The city's perpetual incompleteness attracted artists, anarchists, entrepreneurs, and refugees from more stable places. Rent was cheap because bombs had destroyed most housing stock and politics had frozen development. Possibility filled the gaps. Even now, as Berlin gentrifies and normalizes, the reputation persists: this is where you come when you want to become something else.

Berlin cannot forget its history because Berlin built its history into concrete. The Holocaust Memorial near the Brandenburg Gate covers an entire city block with 2,711 concrete slabs of varying heights - an abstract field meant to produce unease, disorientation, the impossibility of comprehending what happened. The Topography of Terror documents the SS and Gestapo on the very ground where their headquarters stood. Stolpersteine, small brass plaques, are embedded in sidewalks throughout the city marking where Jewish residents were taken for deportation.

The wall itself became a memorial before it was fully demolished. Sections were preserved, sold to collectors, displayed in museums worldwide. The East Side Gallery covers a 1.3-kilometer stretch with murals - including the famous image of East German leader Erich Honecker and Soviet leader Leonid Brezhnev kissing. Memory in Berlin is not optional; it's infrastructure. The city that hosted twentieth-century Europe's greatest crimes and greatest liberation insists that visitors confront both. It's uncomfortable. It's meant to be.