New York’s New Museum has announced plans for a major expansion, which will be completed in time to celebrate its 40th anniversary next year.

The expansion, which will span a building next door that the New Museum already owns, will double the space of the museum, from 58,000 square feet to to a little over 100,000 square feet, the New York Times reports.

The museum announced yesterday that it had raised $43 million out of an $80 million fund-raising campaign to finance the expansion and the museum’s experimental programs and think-tanks—an amount that will triple the size of its endowment.

“We’ve known for a long time that we wanted an expansion, but we’ve been thinking about what an expansion means for a museum like this,” Lisa Phillips, the museum’s director, told the NYT.

“We own the building next door, and it just makes sense to use it. But it was also about thinking about ways to create a parallel structure there, to make something that’s different and a counterpoint to this building,” she added.

According to the NYT, the collector, philanthropist, and longtime supporter of the institution Toby Devan has made the single biggest donation in the New Museum’s history to jump-start the expansion (the exact amount, however, remains undisclosed).

The SANAA-designed museum—small and boxy compared to its Manhattan neighbors, the MoMA and the revamped Whitney—has, regardless of its size and lack of a permanent collection, conquered the art world establishment and the public, thanks to its critically-acclaimed program.

Despite having a modest annual budget of just $13 million (compared to MoMA’s yearly $147 million) the New Museum’s attendance figures have multiplied from 60,000 to over 400,000 yearly visitors since relocating to the Bowery in 2007.

“I think on one hand we’re in an interesting position, because clearly we’ve demonstrated that size doesn’t really matter,” Massimiliano Gioni, the museum’s artistic director, told the NYT. “The specificity of our limits has really almost defined who we are. We’re not going out there and saying that we want to be like all the others,” he added.

The building next door was once a restaurant, before becoming a studio for artists like James Rosenquist and Tom Wesselmann. Right now, it houses the museum’s business incubator, a maverick program to connect artists and entrepreneurs.

Phillips, however, told the NYT that it would take some time to decide what the new expansion would be used for specifically.

“I don’t have it completely laid out, but it’s about trying to do things that museums haven’t done yet or maybe even imagined,” she told the NYT.