This is Japan's most significant business district and home of the Imperial Palace. General Douglas MacArthur commanded his occupation troops from a district office that still exists today. But in more recent history, Marunuchi has become the epicenter of the nation's economy, with more than 25 percent of Japan's GDP coming from the few square miles of this district. Japan's top brands are sold along Naka-dori, Marunuchi's cobblestone main street. From November to February, streets in the area are decorated with nearly 1 million festive lights.