‘The Dark Knight’ and ‘The Avengers’ forbidden sites among dozens of places NYC festivalgoers can tour for one October weekend

A towering Long Island City power plant once featured in box office blockbusters “The Avengers” and “The Dark Knight Rises” highlights dozens of normally roped-off Big Apple locations curious New Yorkers can get a coveted glimpse into – for one weekend only.

The Open House New York Weekend festival returns, offering behind-the-scenes tours of more than 270 otherwise forbidden spots around the city on Oct. 18-20, including the iconic Ravenswood Generating Station – which at times supplies about 20% of NYC’s electricity. 

“It’s a living museum,” said Clint Plummer, the CEO of Rise Light & Power, which owns the plant. “It’s a vital part of keeping the lights on in New York City … and it’s one of those things that the public doesn’t get a look inside. It’s this big piece of infrastructure that’s so omnipresent, so vital in New York.”

This season’s Open House New York Weekend will be the first time in the power plant’s 60-year history it will be granting tours to hardhat-clad visitors, though that’s not to say New Yorkers haven’t noticed the prominent site before.

The plant’s recognizable exterior has been featured in Christopher Nolan’s third installment of his Batman trilogy “The Dark Knight Rises,” Plummer said, as well as “The Avengers” in 2012, Marvel’s first film in the Avengers series.

Plummer hopes visitors will not only be able to see the plant’s decades-long history powered by unionized New Yorkers, but also its future pursuing renewable energy.

Other additions this year include the Bronx Music Hall and Bronx Music Heritage Center, as well as The Players – the city’s oldest private social club in its original Gramercy Park venue.

Clubhouse president Townes Coates highlighted artifacts collected over the club’s 135-year history — from painted portraits of famed members (such as Ethan Hawke, Morgan Freeman and Jimmy Fallon) to the skull that founder Edwin Booth, brother of Lincoln assassin John Wilkes Booth, used in a performance of “Hamlet.”

“It is a house that has amazing architectural elements, it has amazing artistic elements – you truly can experience this in an up close way,” Coates said of the arts-based social club.

Other Open House New York offerings include the textile conservation lab at St. John the Divine – where sacred fabrics are repaired and reconstructed in a repurposed 19th century orphanage connected to the cathedral – tours of an active Tribeca construction site, a hand-painted sign shop and even a Greek revival mansion in the Bronx. 

“It’s the nature of New Yorkers: they’re almost by definition, curious,” said Kristin LaBuz, the executive director of Open House NY, who expects the 7,000 available tickets to sell out quickly this week.

“If there’s one thing New Yorkers love more than anything, it’s access,” she added. “It’s seeing something nobody else can see.”

Some returning highlights for the 21-year-old festival include the former Brooklyn Rapid Transit Power Station (now Powerhouse Arts), the recently reopened Lewis Latimer House Museum in Queens and the UN Headquarters.

The first Open House New York weekend debuted two decades ago after architect Scott Lauer visited a similar expo in London, LaBuz told The Post. It was after 9/11 that Lauer and a grassroots group of architects teamed up to open up local spaces in order to bring New Yorkers together again.

“It’s the simple act of discovering something new – a new policy [or] a new idea – and talking to people who you may not talk to every day,” LaBuz said of the festival. “It gives access to things hidden in plain sight.”

Variations of the festival have since been held in about 60 cities around the world, from Zurich to Athens, the executive director said.

Tickets go on sale online at 11 a.m. Tuesday. A full roster of open sites and respective hours can be found on the Open House NY Weekend website. The majority of the tours are free.