nightless city; city that never sleeps
Refers to a bustling entertainment district or city where lights and activity continue all night. Often used for historical or literary descriptions of pleasure quarters, but also for modern cities like New York or Tokyo.
Yoshiwara was once called a nightless city.
Tokyo is truly a city that never sleeps.
Borrowed from Chinese 不夜城, literally “city without night.” In Japanese it came to denote a brightly illuminated district or city active throughout the night.