While the Berlin Wall stood, Potsdamer Platz was a sort of No Man's Land in Berlin; it was illuminated at night to prevent defection and was, generally, Not A Nice Place. After the wall was opened in 1989, most of the wall quickly came down, leaving only small bits. In 1999, the Berlin government had most of the rest removed (why they don't just take the whole thing down is beyond me. They could leave a small section as a tourist attraction, but for Pete's sake, tear the thing down). Potsdamer Platz is considered, by some, to be a "city in a city" inside of Berlin due to its rapid economic growth since the opening of the wall.