Twenty eight works of art, including one by Picasso, have been stolen from a warehouse near Madrid.
Police said three masked men broke into the warehouse in Getafe and took a lorry containing the works, worth about 5 million euros $US6.6 million).
The theft took place on Saturday.
The works had been on display in Germany and were due to be delivered to galleries in Madrid, Barcelona and Cologne.
Among the missing paintings, lithographs and sculptures are works by Spanish sculptor Eduardo Chillida, Pablo Picasso, Antonio Saura and Colombian artist Fernando Botero.
The BBC reports many were not insured.