Rembrandt “The Night Watch” / butter knife, acid, city officials
(This 1642 painting has been damaged by vandals on numerous occasions:
1.) In 1715, the town fathers of Amsterdam decided to install the painting in their Town Hall. Because the painting was too large to fit in their chosen display location, they proceeded to cut off sections of the painting on all four sides. They removed two figures on the left side of the painting as well as the top of the arch, the balustrade, and the edge of the step.)
2.) During World War I, an unemployed shoemaker made several knife slashes in the artwork to protest his inability to find work.
3.) In 1975, an unemployed school teacher named Wilhelmus de Rijk attacked it with a bread knife, resulting in a large zig-zag of slashes. It was successfully restored, although some evidence of the damage is still observable up close. (Learn more here: http://art-damaged.tumblr.com/post/172346857520/rembrandt-the-night-watch-1642-bread-knife-in)
4.) In 1990, a man sprayed acid onto the painting with a concealed pump bottle. Security guards intervened and water was quickly sprayed onto the canvas. The resulting damage was minimal - the acid had only penetrated the varnish layer - and the painting was fully restored.