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)

A female street art collective has set a new Guinness World Record to create the largest spray-painted mural by multiple artists. Over 100 international female street artists came together to create the continuous mural in south London’s Leake Street Tunnel, made famous by Banksy, on March 8, 2014. The record was broken as part of all-female street art event Femme Fierce, the largest of its kind in the UK, which aims to celebrate women street artists across the world. Photo: Zabou's witty graffiti. (Photo by Dez Mighty/Susan Mackey)

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)

A Kurdish fighter from the People's Protection Units (YPG) fires his rifle at Islamic State militants as he runs across a street in Raqqa, Syria, July 2017. (Photo by Goran Tomasevic/Reuters)

Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province June 30, 2014. The fighters held the parade to celebrate their declaration of an Islamic “caliphate” after the group captured territory in neighbouring Iraq, a monitoring service said. The Islamic State, an al Qaeda offshoot previously known as Islamic State in Iraq and the Levant (ISIL), posted pictures online on Sunday of people waving black flags from cars and holding guns in the air, the SITE monitoring service said. (Photo by Reuters/Stringer)

In this Tuesday, July 14, 2015, photo, Phoe Thaw, center, a member of the White New Blood lethwei fighters club, a Myanmar traditional martial-arts club which practices a rough form of kickboxing, stretches during a practice session in their gym on a street in Oakalarpa, north of Yangon, Myanmar. Three of the club's members competed this summer on a stage a world away from the street gym: a mixed-martial-arts “One Championship” event broadcast globally on cable television networks, where fighters could receive $1,000 for each fight, according to coach Myint Zaw who started the traditional fighters' club 15 years ago. (Photo by Gemunu Amarasinghe/AP Photo)