In 1590, an exiled samurai was given a worthless swamp as punishment. He built a city. Today it holds 37 million people, the world's busiest train station, and six visible historical layers. Here's how to see all of it — district by district, century by century.
Edo Castle was once the largest castle ever built. Tokyo's Imperial Palace today is its surviving outer wall — plus the 5km loop locals run counterclockwise every dawn. Here's how to walk 400 years of Japanese history for free.