You'd think that a 42-ton (38-metric-ton) sculpture would be pretty difficult to lose. After all, it consisted of four 5-foot-wide (1.5-meters-wide) blocks of steel with an empty space between each block [source: Art Newspaper]. But that's exactly what happened to "Equal-Parallel: Guernica-Bengasi," a 1986 work by sculptor Richard Serra. The sculpture, commissioned by Madrid's Reina Sofia Contemporary Art Museum, was put on display there for four years after its creation. But in 1990, when the museum's management embarked upon a renovation, it decided the piece was too big, and it was shipped off to a private storage facility.
Fifteen years later, in 2005, the museum's recently installed director, Ana Martinez de Aguilar, decided to retrieve "Equal-Parallel: Guernica-Bengasi" and once again exhibit it. She discovered that the storage company had gone into receivership and that the sculpture — whose paper trail ended in 1992 — was embarrassingly nowhere to be found. Serra, to his credit, agreed to create a new, identical copy of his sculpture for the museum, with the institution picking up only the cost of the fabrication at a German foundry [source: Art Newspaper].