A group of art activists have climbed on to the roof of the presidiential palace in Prague to replace the president's flag with a huge pair of underpants.
The three men dressed up as chimney sweeps, and managed to get onto the roof to remove the official flag belonging to the country's President, Milos Zeman.
They then raised a giant pair of red boxer shorts above the palace, in a protest against some of the actions of the President.
Ztohoven released a statement on their website, saying: "Today we hung a banner over the castle for a man who is not ashamed of anything."
The men from the Ztohoven art collective have been arrested, and could face up to two years in prison for their actions.
Police spokeswoman Andrea Zoulova said that three people had been detained on suspicion of disorderly conduct and theft, but were released while the investigation continues.