MADRID, Spain (AFP) — Spanish police are investigating the disappearance of a Pablo Picasso painting, which vanished while in transit from Madrid to the southern city of Granada for an exhibition, authorities said Thursday.

“Still Life with Guitar“, an oil-on-canvas painting valued at 600,000 euros ($700,000), was scheduled to go on display at an exhibition organised by the CajaGranada foundation last week, local newspaper Ideal reported.

All pieces in the show come from private collections, the foundation said.

National police sources confirmed that the painting’s disappearance was under investigation but provided no further details, citing confidentiality rules.

Thieves have frequently targeted Picasso works given their high value — two of his paintings sold for more than $140 million at auctions in recent years.

One of the most notorious thefts occurred in 1976, when more than 100 of the artist’s paintings were stolen from the Palais des Papes museum in Avignon, southern France.

All of the works were eventually recovered.

Picasso, who was born in 1881 in Malaga in southern Spain and died in 1973, is widely acknowledged as one of the most important artists of all time.

He challenged conventional ideas and experimented with a wide range of styles and themes throughout his long career.