The museum Mauritshuis said in a statement that the work behind the glass had been examined by its restorers and had not been damaged. “Art is defenceless, and the Mauritshuis strongly rejects trying to damage it for whatever purpose,” it said. It comes after members of a German environmental group, Letzte Generation (Last Generation), threw mashed potatoes over Claude Monet’s Les Meules (Haystacks) in the Museum Barberini in Potsdam, outside Berlin, on Sunday. Ten days previously, Just Stop Oil activists emptied tomato soup over Vincent van Gogh’s Sunflowers at the National Gallery in London before glueing themselves to the wall beneath the artwork, one of the gallery’s most important treasures. Les Meules and Sunflowers were also behind glass. “How do you feel when you see something beautiful and priceless being destroyed before your eyes?” asked one of the protesters in The Hague. “Do you feel outraged? Good. Where is that feeling when you see the planet being destroyed?” To cries of “Shame on you!,” “Obscene”, “Stupid”, and “Get away from there” from visitors to the gallery, he said the painting was “protected by glass and is just fine”, but that “the future of our children” was not. Dutch police have arrested three people at the Mauritshuis museum.