Revellers take part in the Children's Day parade of the Notting Hill Carnival in London, Britain, 28 August 2016. The street festival celebrates this year its 52nd anniversary and more than a million people are expected to attend on 28 and 29 August. (Photo by Will Oliver/EPA)

Tube passengers take a selfie next to a London underground roundel designed for the launching of the Night Tubes on display at Oxford Circus underground station in London, Britain, 19 August 2016. The long delayed Night Tubes service launched on 19 August. The 24-hour service will operate on Fridays and Saturdays. (Photo by Hannah Mckay/EPA)

Performers are reflected in a displayed vehicle before going onto the stage during the Auto China 2016 auto show in Beijing, China, April 29, 2016. (Photo by Damir Sagolj/Reuters)

Clowns and entertainers gather to attend an annual service of remembrance in honour of British clown Joseph Grimaldi at All Saints Church in Haggerston in London, Britain, February 5, 2017. (Photo by Toby Melville/Reuters)

This combination picture shows some revellers wearing masks while dressed as “Botargas” during carnival celebrations in Almiruete, Spain, February 25, 2017. (Photo by Sergio Perez/Reuters)

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)

An Israeli soldier leaves the battlefield after an army exercise on at the Shizafon army base, in the Negev Desert north of the southern city of Eilat on January 31, 2012 in Shizafon, Israel. (Photo by Uriel Sinai/Getty Images)

Men stroll past roadside vendors as a painted truck makes its way through the busy street in Kabul, Afghanistan, November, 1961. (Photo by Henry S. Bradsher/AP Photo via The Atlantic)