There's an empty space today where a Henri Matisse painting had been hanging at the Kunsthal museum in Rotterdam, Netherlands. Seven paintings were stolen Tuesday, including works by Pablo Picasso, Claude Monet and Paul Gauguin. Peter Dejong/AP hide caption

itoggle caption Peter Dejong/AP

Roy Lichtenstein leaves it up to the viewers to decide what has just transpired in his 1964 painting of a tense phone call titled Ohhh ... Alright ... Estate of Roy Lichtenstein hide caption

itoggle caption Estate of Roy Lichtenstein

Alfredo Ramos Martinez painted Head of a Nun, tempera on newspaper, in 1934. Gerard Vuilleumier/The Alfredo Ramos Martinez Research Project, Reproduced by Permission hide caption

itoggle caption Gerard Vuilleumier/The Alfredo Ramos Martinez Research Project, Reproduced by Permission

Alfred Hair, Harold Newton, Al Black, James Gibson and Mary Ann Carroll were all part of the original Highwaymen. Photos by Gary Monroe hide caption

itoggle caption Photos by Gary Monroe

Industrial designer Raymond Loewy purchased Pablo Picasso's Seated Woman with Red Hat (or Femme assise au chapeau rouge) in 1957 and gifted it to the Evansville Museum in the '60s. AP/Courtesy Evansville Museum of Arts, History & Science, Michael Wheatley hide caption

itoggle caption AP/Courtesy Evansville Museum of Arts, History & Science, Michael Wheatley

Knitting Is for Pus**** is a work by crochet sculptor Olek. He has created an entire apartment blanketed in brightly colored, crocheted camouflage. Olek/Courtesy Jonathan LeVine Gallery, New York, N.Y. hide caption

itoggle caption Olek/Courtesy Jonathan LeVine Gallery, New York, N.Y.

Twain's boyhood home in Hannibal, pictured circa 1955, is now a museum. Three Lions/Getty Images hide caption

itoggle caption Three Lions/Getty Images

After John F. Herring by Ken Perenyi, circa 1989. Courtesy of Pegasus Books hide caption

itoggle caption Courtesy of Pegasus Books