De Wallen is the oldest part of Amsterdam. The lanes and small canals east of Dam Square are medieval, the city's first harbour district, and sailors, drink and sex have been part of it for most of seven hundred years. Sex work here is legal, licensed and taxed — the Netherlands lifted the ban on brothels in 2000, bringing the trade under labour and health regulation rather than trying to end it — and it is done from ground-floor windows edged in red. Cannabis is sold in permitted coffeeshops under a policy that tolerates the retail while the supply remains illegal, a contradiction the Dutch acknowledge and call the back-door problem.
In the middle of all this stands the Oude Kerk, consecrated around 1306 and the oldest building in the city, with the windows glowing red around its churchyard. That collision is the district, and by daylight it is a different place: quiet, genuinely pretty, some very good small canals, and the church open. After dark the lanes fill and the city's long argument about what mass tourism has done to this quarter becomes visible on the pavement.