Red Light District (De Wallen)

Amsterdam's most infamous neighborhood has been in the business of sin since the 1300s, which makes it one of the oldest continuously operating red-light districts on the planet. Locals call it De Wallen — "the walls" — after the old city walls that once ran through here. When Amsterdam was a booming port in the 14th and 15th centuries, sailors waiting for ships to depart would wander these narrow lanes looking for beer and company, and the neighborhood was happy to provide both.

What surprises most visitors is how small and beautiful De Wallen actually is. These are some of Amsterdam's oldest and most picturesque canals, lined with leaning medieval buildings and crossed by tiny bridges. The famous red-lit windows occupy only a few streets within a much larger historic quarter that also contains the Oude Kerk, some of the city's best Indonesian restaurants, and a Buddhist temple tucked into an alley.

The Netherlands formally legalized prostitution in 2000, and De Wallen operates under strict regulations — sex workers pay taxes, have regular health checks, and are protected by labor law. But the neighborhood has been shrinking for years. City officials have been buying up window space and converting it into fashion boutiques and art galleries through a gentrification program called Project 1012, named after the postal code.

Walk through at different times of day and you get completely different cities. Morning: quiet canals, locals on bicycles, the Oude Kerk bell ringing. Evening: a river of tourists, red neon reflections on the water, and the unmistakable feeling that you're somewhere no other city would dare to build.