Broadway went dark. Streets emptied out. Mayor Bill de Blasio urged a moratorium on children’s outdoor fun.

The city that never sleeps hit the snooze button Saturday to cope with one of the heaviest snowfalls on record, dating to 1869.

Citing a state-ordered travel ban barring nonemergency motorists from the roads and the closure of all but underground subways, de Blasio asked stores to close early and avoid stranding workers.

“It’s time for businesses to shut down and get their employees home right away,” de Blasio said.

The NYPD threatened to arrest motorists who ignored the travel ban. As of 7:30 p.m., more than 25 inches of snow had fallen at Central Park, the third-highest total ever.

“We need our cops to be able to answer calls for service — not lock up people who make bad decisions by staying out on the road,” said Chief of Department James P. O’Neill.

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Within hours of de Blasio pleading that Broadway theaters cancel their shows, the industry obliged, calling off matinee and evening performances, according to the Broadway League, which represents the district’s 40 theaters. The league expected shows to resume Sunday.

In December 2010, de Blasio’s predecessor, Michael Bloomberg, advised residents complaining about unplowed outerborough streets in a similar storm to enjoy the snow or take in a Broadway show.

On Saturday, de Blasio said everyone — city dwellers, suburbanites, workers delivering takeout food and children — should return home and stay indoors.

“I understand fully kids clamoring for fun in the snow, but my best advice is, either don’t go out, or go out very briefly, and keep a very close eye on your kids,” he said. “There will be time for fun in the snow tomorrow.”