BOSTON — An exhibit opening at Boston’s Isabella Stewart Gardner Museum highlights some of the masterpieces stolen 23 years ago in one of the world’s most infamous art heists.

No, the 13 works by Rembrandt, Vermeer, Manet and others, have not been recovered.

Rather, the Sophie Calle exhibit, “Last Seen,” features photographs of the empty frames and spaces where the paintings worth hundreds of millions of dollars hung, along with text from interviews with museum staff.

Some images have been displayed around the world for two decades.

A recent expansion of the Gardner Museum means they can finally be displayed in Boston, along with five new pieces never shown publicly before.

FBI officials have said they think they know who stole the works in 1990, but the artwork has not been recovered.