The city has ordered a stop to renovations at a Washington Square site because vibrations from the work were threatening a hundred-year-old Maxfield Parrish mural in the building, officials said Monday.

The Pennsylvania Academy of the Fine Arts, which owns the Dream Garden mural in the Curtis Center, alerted the city about its concerns Thursday. The city issued an order halting construction the next day.

The city said work would be suspended until stronger protections for the mural, which is made up of hundreds of thousands of pieces of glass, are put in place.

"Dream Garden is a priceless artistic and historic treasure under the protection of PAFA and the Historic Commission for the people of Philadelphia," Licenses and Inspections Commissioner David Perri said in a statement. "L&I will work with everyone involved to figure out the best resolution to the situation; resuming construction without keeping the mural safe is off the table."

A spokeswoman for L&I said the renovations were being made to the interior of the atrium at the Curtis Center. The building is owned by Keystone Property Group.

In a statement, Keystone said the company is a steward of history and has "taken great care to preserve the beauty and history of the local architecture, as well as the Dream Garden mural."

"We will continue to take every necessary precaution to ensure that all of the unique and historic features of our buildings are fully maintained," the company said.

The 15-by-49-foot mural was designed by Parrish. Its installation, competed in 1916, took a year and the efforts of 30 artists.

This is the second time the city has stepped in to protect Dream Garden.

Eighteen years ago, the mural was almost sold to the casino magnate Steve Wynn, who planned to move it to Las Vegas. The Historic Commission designated the mural a historic object under city code. The city spent three years fighting off legal challenges to the designation.

In 2001, the Pew Charitable Trusts donated $3.5 million to allow PAFA to purchase the mural, with the understanding that it remain in the Curtis Center.

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@TriciaNadolny