Israeli police officers confront demonstrators as Israelis protest against rising housing prices and social inequalities on July 30, 2011 in Tel Aviv, Israel. Tens of thousands of Israelis took to the streets in 10 cities across the country to protest against the high cost of living, including more than 50,000 in downtown Tel Aviv. The demonstrators rallied in support of hundreds of people who have set up protest camps against the government's economic and social policies. (Photo by Uriel Sinai/Getty Images)

British Gas engineer Martin Caulfield, 69, services and cleans a gas lamp in front of Big Ben on October 31, 2011 in London, England. Caulfield has been looking after the traditional lights since 1982. There are still around 1600 left in the capital. (Photo by Matthew Lloyd/Getty Images)

The space shuttle Endeavour is transported to the California Science Center in Exposition Park from Los Angeles International Airport (LAX) in Los Angeles, California. (Photo by Kevork Djansezian)

Supermodel Iman (center) introduces her husband David Bowie (L) to Rihanna (R) at the DKMS' 5th Annual Gala: Linked Against Leukemia honoring Rihanna & Michael Clinton hosted by Katharina Harf at Cipriani Wall Street on April 28, 2011 in New York City. (Photo by Andrew H. Walker/Getty Images for DKMS)

In this September 1, 2015 photo, street artists Jenaro de Rosenzweig, left, and Alejandro Revilla pose for a portrait behind a restaurant's window covered with a mural by artist Francisco Munoz, signed with his artist's name below, in the Roma Norte neighborhood of Mexico City. Rosenzweig and Revilla founded the “Street Art Chilango” cooperative in March 2013, which is filling neighborhoods with public art by local street artists. (Photo by Rebecca Blackwell/AP Photo)

A woman greets a street artist at the San Fermin festival in Pamplona, northern Spain July 8, 2016. (Photo by Eloy Alonso/Reuters)

A man passes by an unfinished street art graffiti made in a stairway by French street artists Zag and Sia in Paris on March 1, 2016. The two artists drew inspiration from famous “Liberty Leading the People” (La Liberte guidant le peuple) painting by French Eugene Delacroix commemorating the July Revolution of 1830 and viewed as a symbol of the French Republic. (Photo by Joel Saget/AFP Photo)

An artists performs on the street during a Myfest festival marking the May Day in the Kreuzberg district in Berlin, Germany on May 1, 2018. (Photo by Fabrizio Bensch/Reuters)