CHRISTMAS IS BIG business in the Big Apple and nowhere is this point brought home more persuasively than in the entertainment heart of Manhattan.

I’m talking about that most middle American of attractions — the Radio City Christmas Spectacular — which has been running non-stop every holiday season since 1979.

The centerpiece of the show, the 36-strong Rockettes, have been high-kicking since 1925, starting off, appropriately enough, in the heartland of America, St. Louis, as the Missouri Rockets. The precision dance troupe performed at the opening of Radio City on Dec. 27, 1932, alongside the Flying Wallendas and Martha Graham. They were an instant sensation.

However, the Christmas Spectacular remained a “gift” to audiences, as a entertaining intermission between feature attractions through the ’70s.

Having become a moneymaker in the ’80s, the 90-minute Christmas Spectacular now attracts 1 million ticketbuyers each nine-week season (Nov. 3-Jan. 2) — more than will have seen Broadway’s hottest show “Spamalot” in a year.

Like several other fiercely defended New York phenoms — the Macys Thanksgiving Day parade, the shellfish at the Oyster Bar, the skating rink in Central Park — the Spectacular is almost impervious to criticism.

This season’s edition has, however, been momentarily hampered by a musicians strike — Radio City Entertainment wanted to bring in a second set of 35 musicians for the exhausting run and cut the present set’s overtime pay. So far taped music does not seem to have dented ticket sales.

The performance Daily Variety caught appeared sold out, with tickets costing between $40 and $250. The top is more than twice the price of the most expensive Broadway seat, but then again Radio City is no ordinary theater. With its 6,000 seats, the Christmas Spectacular brought in $74 million last season and is on track to do the same this go-round.

RCE is part of the Madison Square Garden unit of Cablevision, which accounts for 12% to 15% of the company’s revenues each quarter. The entertainment venue is generally considered a bright spot in Cablevision’s portfolio.

Even so, it nowadays takes 250 people to stage the show (as many as six perfs only weekends), with performers going though 1,300 costumes and 1,200 pairs of pantyhose during the run. There’s also a backstage zoo that houses the Music Hall Menagerie — an unlikely herd of two donkeys, three camels, six sheep and a horse that perform in the Living Nativity sequence. In all, the country’s No. 1 live stage show employs 600 people during the holiday season. (Reps suggest most of the proceeds are ploughed back into the show, though specifics were not available.)

IT WOULD BE CHURLISH as well as pointless to critique the show (and most Gotham papers don’t bother) as the precision drills of the chorus line (especially in the Parade of the Wooden Soldiers and Reindeer antler sequences) never fail to please, however middling some of the other elements (the singing, the acting) might from time to time be.

The show is an unapologetic plug for the secular society, especially as experienced in the Big Apple. One fairly new sequence called White Christmas in New York features the Rockettes as mannequins in Fifth Avenue shop windows who are magically transformed into dancing snowflakes.

And even as the producers strive to update everything from the costumes to the lighting to the special effects, there’s something retro in the show’s appeal.

You could for a moment imagine you’re in the 1950s — before political correctness, before the culture wars, before some folks began eshewing the expression Merry Christmas altogether in favor of Happy Holidays.

For 80 minutes or so the show revolves around the Santa Claus theme, and the letters (and now emails) that Kris Kringle receives from kids. The most eye-poppingly elaborate sequence is set in Santa’s workshop at the North Pole (complete with six “little people” who perform as elves), which is all about getting the gifts ready for the midnight sleigh ride.

Then the tone shifts to the overtly sacred: Santa says it’s really all about caring for those near and dear to us, not about getting gifts. The final scene is the Living Nativity complete with manger, wise men — and the aforementioned animals. The mighty Wurlitzer plays “Joy to the World” and the loudspeaker intones “The Solitary Life.”

In part, it went, “Over 2,000 years have passed, and He (Jesus’ name is never mentioned) is the central figure for much of the human race. All the armies that ever marched and all the kings that ever reigned put together have not affected the life of man upon this earth as powerfully as this one solitary life.”

At the performance Daily Variety attended — in one of the most polyglot, culturally and religiously diverse cities in the world — a noticeable minority of the grownups applauded fervently.

THE CHRISTMAS SPECTACULAR is not the town’s only take on the holiday.

  • The Gay Men’s Chorus, perform carols at Carnegie Hall Dec. 14.

  • The Tractenburg Family Slideshow Players — performing on ice no less — bring their wacky holiday musical to Performance Space 122 Dec. 18-23.

  • The Christmas Revels, a medieval winter solstice celebration, recreates entertainment circa the year 1399 at Symphony Space Dec. 9-11.

Follow @Variety on Twitter for breaking news, reviews and more