People pass a new mural depicting Britain's Queen Elizabeth II spray painted onto an external wall of a house in south-east London, Britain, 16 May 2016. The artwork is created by Banksy-style street painter “Catman”. (Photo by Hannah Mckay/EPA)





A pedestrian passes a mural of Muhammad Ali painted on the side of a building Monday, June 6, 2016, in Louisville, Ky. The president of Turkey and king of Jordan joined the long line of world leaders, religious figures and superstars set to speak at Ali's funeral Friday. (Photo by David Goldman/AP Photo)





Artist Binho from Brazil paints his work on a building during the International Festival of Street Art in Sao Paulo October 24, 2015. (Photo by Nacho Doce/Reuters)





Artists Binho (R) from Brazil and Suiko from Japan paint their works on a building during the International Festival of Street Art in Sao Paulo October 24, 2015. (Photo by Nacho Doce/Reuters)





Aleksei Bordusov aka AEC, better known as Interesni Kazki, from Ukraine, paints his work on a building during the International Festival of Street Art in Sao Paulo October 24, 2015. (Photo by Nacho Doce/Reuters)





Tinho and Carlos Vergara (R), from Brazil, paint their work on a building during the International Festival of Street Art in Sao Paulo October 24, 2015. (Photo by Nacho Doce/Reuters)





A Palestinian boy walks past graffiti painted on the controversial Israeli barrier in the West Bank town of Bethlehem, April 27, 2016. (Photo by Ammar Awad/Reuters)





A Palestinian walks past graffiti painted on the controversial Israeli barrier in the West Bank town of Bethlehem, April 27, 2016. (Photo by Ammar Awad/Reuters)





A Palestinian boy rides a bicycle as he passes a graffiti on the controversial Israeli barrier in the West Bank town of Bethlehem, April 27, 2016. (Photo by Ammar Awad/Reuters)





A foreigner takes a picture with her mobile phone near a graffiti painted on the controversial Israeli barrier in the West Bank town of Bethlehem, May 2, 2016. (Photo by Ammar Awad/Reuters)





A Palestinian boy walks past graffiti on the controversial Israeli barrier in the West Bank town of Bethlehem, April 27, 2016. Picture taken April 27, 2016. (Photo by Ammar Awad/Reuters)





People sit in front of a mural as they wait for travel permits to cross into Egypt through the Rafah border crossing after it was opened for two days by Egyptian authorities, in the southern Gaza Strip May 11, 2016. (Photo by Suhaib Salem/Reuters)





Graffiti of a Storm Trooper from Star Wars is seen on the pier in Malin Head in Ireland, May 11, 2016. (Photo by Clodagh Kilcoyne/Reuters)





A Palestinian boy plays with a ball in front of a mural at Deir al-Balah refugee camp in the central Gaza Strip May 16, 2016. (Photo by Suhaib Salem/Reuters)





Palestinian children play near murals at Deir al-Balah refugee camp in the central Gaza Strip May 16, 2016. (Photo by Suhaib Salem/Reuters)





A girl waits with her family for a travel permit to cross into Egypt through the Rafah border crossing after it was opened for four days by Egyptian authorities, in the southern Gaza Strip June 1, 2016. (Photo by Suhaib Salem/Reuters)





A woman walks past a grafitti mural in downtown Buenos Aires, Argentina, June 1, 2016. (Photo by Marcos Brindicci/Reuters)





Reception class school children skip past a mural, attributed to graffiti artist Banksy, painted on the outside of a class room at the Bridge Farm Primary School in Bristol, Britain June 6, 2016. (Photo by Dylan Martinez/Reuters)





A man walks past a mural June 27, 2005 in downtown New London, Connecticut. (Photo by Spencer Platt/Getty Images)





People stand by grafitti near a procession celebrating the holiday of Corpus Christi on May 26, 2016 in Rio de Janeiro, Brazil. The tradition is marked on the eighth Thursday following Easter and commemorates the ritual of the Eucharist. Brazil is home to the largest number of Roman Catholics in the world and will host the Rio 2016 Olympic Games in August amid an economic and political crisis. (Photo by Mario Tama/Getty Images)





A man walks past a sign reading “We Must Stop Killing Each Other” in the neighborhood where Freddie Gray was arrested last year in Baltimore, Maryland, on May 23, 2016. (Photo by Nicholas Kamm/AFP Photo)





In this May 28, 2016 photo, a motorcycle taxi rides past a wall blanketed with murals in Petion-Ville, a suburb of Port-au-Prince, Haiti. (Photo by Dieu Nalio Chery/AP Photo)





A Yemeni passes a wall sprayed with anti-smoking graffiti on World No Tobacco Day in Sana’a, Yemen, 31 May 2016. World No Tobacco Day is marked annually on 31 May to raise awareness of the health risks of tobacco use and to push advocacy for policies to reduce tobacco consumption. (Photo by Yahya Arhab/EPA)





Two Palestinian boys play on a donkey cart next to a wall of graffiti in Deir el-Balah refugee camp, central Gaza Strip, Wednesday, June 1, 2016. (Photo by Khalil Hamra/AP Photo)





In this May 11, 2016 photo, a taxi drives past the Cuauhtemoc Housing Unit and a municipal sign with a message that reads in Spanish; “Building the new Acapulco” in Acapulco, Mexico. (Photo by Enric Marti/AP Photo)





This May 11, 2016 photo shows the backside of a bus decorated with a provocative mural, in Acapulco, Mexico. (Photo by Enric Marti/AP Photo)





A general view taken on May 16, 2016 shows graffiti in Gaza City commemorating the “Nakba” or “catastrophe” in Arabic in reference to the establishment in 1948 of the state of Israel 68-years-ago in British-mandate Palestine, which led to the displacement of hundreds of thousands of Palestinians who either fled or were driven out of their homes during the 1948 war over Israel's creation. (Photo by Mohammed Abed/AFP Photo)