No, New York City is not the only city with a 24/7 subway, though it is one of the most famous for it. In 2026, other systems that offer 24/7 service include the Chicago "L" (specifically the Red and Blue lines) and the PATH train connecting NJ and NY. Internationally, the Copenhagen Metro operates 24/7, and several lines of the London Underground (the "Night Tube") and the Berlin U-Bahn operate all night on weekends. Some cities, like Tokyo and Seoul, do not run 24/7, shutting down for a few hours of maintenance in the early morning. What makes the NYC Subway unique in 2026 is that all 27 of its lines are designed for 24-hour operation every day of the year, enabled by its "quad-track" layout in many areas, which allows trains to be rerouted to express tracks while maintenance occurs on local tracks. This infrastructure makes NYC the only mega-city where the entire heavy-rail network never officially sleeps, supporting the city's 2026 workforce and nightlife.