A street cleaner demonstrates his martial arts skills in front of a closed shop near Beijing's Tiananmen Square September 2, 2015 as the capital prepares for tomorrow's parade. (Photo by Damir Sagolj/Reuters)

An young Indian Jain devotee dressed as Lord Krishna participates in a religious rally organised on the occasion of Mahavir Jayanti in Kolkata on April 2, 2015. The most important religious holiday in Jainism, Mahavir Jayanti celebrates the birth of Mahavira, the last Tirthankara, which is generally accepted as 599 BCE. (Photo by Dibyangshu Sarkar/AFP Photo)

A window cleaner passes a lighter to his colleague while rappelling from a new building in Tianjin March 23, 2007. (Photo by Reuters/Stringer)

These photographs are the work of urban explorer Dr Bradley Garrett who made headlines back in 2012 when he posted a series of snaps from the top of The Shard skyscraper while it was still under construction. Garrett, now a researcher at the University of Oxford, took these shots during his time with the London Consolidation Crew (LCC), a loose collection of urban explorers based in the English capital. Photo: Bradley Garrett stands on the edge of the Ritz-Carlton Chicago as lightning strikes in the distance in Chicago, US. (Photo by Bradley L. Garrett/Barcroft Media)

A dog takes a dip in the river Elbe on February 6, 2012 in Hamburg, Germany.The current cold front that has claimed over 200 lives in eastern Europe makes its way west. (Photo by Stuart Franklin/Getty Images)

LAPD chopper flies in a foregraund of the Super Moon in Los Angeles, California on May 05, 2012. Tonight's moon is set to appear 14 percent larger and 30 percent brighter from our perspective on Earth. The Supermoon lines up much closely with perigee – the moon's closest point to Earth. The 2012 May full moon falls some six minutes after perigee, the moon's closest point to Earth for this month. At perigee, the moon lies only 221,802 miles (356,955 kilometers ) away. Later this month, on May 19, the moon will swing out to apogee – its farthest point for the month – at 252,555 miles (406,448 kilometers) distant. (Photo by AFP/File, Joe Klamar)

A girl carries a bag of recyclable items she collected from a landfill on the outskirts of Sanaa, Yemen November 16, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

Armed Yemeni children sit in the back of a pick up truck with fighters loyal to Yemen's Saudi-backed President Abedrabbo Mansour Hadi in the Dar saad neighbourhood of the southern Yemeni city of Aden on May 10, 2015, as they continue to battle Shiite Huthi rebels. (Photo by Saleh Al-Obeidi/AFP Photo)