In the last century, the art world has been transformed by controversy. Artists have asked the big question "what is art?" and a succession of crazy artworks have followed.
With more freedom of expression, the main themes tackled are politics, morality, sexuality, and nudity. From Andy Warhol's prints to Yoko Ono's performance pieces, this gallery looks at the works that have caused the most outrage.
If you're curious about the artworks that have angered onlookers and shaped how we view art, click through.