While the idea of covering its courtyard sounded like an interesting idea, the Smithsonian’s Hirshhorn Museum and Sculpture Garden finally cancelled plans to do that citing financial uncertainties.

According to The Associated Press, the project would have cost $15.5 million and was designed by Diller Scofidio + Renfro as a special venue for arts events. Four years ago, when the project was born, it was estimated that it would cost $7 million, but that estimate ballooned to $12.5 million. It would cost another few million to take it down and store it when events weren’t scheduled.

The New York Times reports that the Smithsonian's under secretary for history, art and culture, Richard Kurin made the announcement on Wednesday, adding that Richard Koshalek will resign at the end of the month. Kerry Brougher is going to be the acting director until a full-time replacement is named.

“Without the full support of the museum’s board and the funding in place for the fabrication and a viable plan for the operation of the Bubble, we believe it is irresponsible to go forward,” Kurin’s announcement read. “Architects, artists and Smithsonian staff have praised the bold vision of a temporary bubble-shaped structure on the Mall, but after four years of planning and fundraising, there was not enough funding to construct the Bubble and, more importantly, to sustain programming for years to come.”

The bubble, called the Hirshhorn’s Seasonal Inflatable Structure, would only have been up for two months a year, a sticking point for sponsors who hoped to have their names attached to a permanent structure. Koshalek was a driving force behind the project, but the lack of support from the board of trustees ultimately lead to his resignation.

The Hirshhorn's attendance has been up under his tenure, though. In 2012, it hosted an exhibition by Chinese artist Ai Weiwei. The museum is located on the National Mall.