On a Sunday afternoon earlier this summer, hundreds of Turkish men disappeared down a short alleyway just a five-minute walk from the Istanbul Modern art museum. Some flicked prayer beads around their fingers. The younger ones arrived in small groups, flashing nervous grins and smoothing their hair down with spit. They strode by a pile of garbage bags holding wadded-up tissues and cigarette butts before reaching a metal gate that separated the alley from their destination: Kadem Street, a narrow cul-de-sac and one of the country’s few remaining red-light districts.

A policeman scanned the men’s identification cards and ushered them through a metal detector and into the fray, where voluptuous women in bras and underwear occupied the doorways of the half-dozen houses that lined the street. Minors were refused entry. Minors who could afford a 20-lira bribe were not.

Since the 1870s, prostitution has thrived in Istanbul’s Beyoglu district, which houses Kadem and its sister street, Zurafa. For five decades, an Armenian businesswoman, Matild Manukyan, ran an empire of Beyoglu brothels that netted her an estimated $4 million annually until her death in 2001. Sunday, the last day of rest before the workweek, always brought her particularly brisk business.

Now, the alleyway leading to Kadem is lined with plumbing and appliance shops, all of which are closed on Sunday. For most of the day, the only commerce on the street consisted of a man hawking peeled cucumbers from a wooden cart at one end and a shoe shiner with bloodshot eyes and a raspy voice at the other. Midafternoon, a man trudged by with another cart, this one bearing bananas.