A “creuseur”, or digger, a plastic lantern on his head, readies to enter a copper and cobalt mine in Kawama, Democratic Republic of Congo on June 8, 2016. Cobalt is used in the batteries for electric cars and mobile phones. Working conditions are dangerous, often with no safety equipment or structural support for the tunnels. The diggers say they are paid on average US$2-3/day. (Photo by Michael Robinson Chavez/The Washington Post)

A miner with a donkey makes his way through the low and narrow tunnel leading out of a coal mine in Choa Saidan Shah in Punjab province, April 29, 2014. Workers at this mine in Choa Saidan Shah dig coal with pick axes, break it up and load it onto donkeys to be transported to the surface. Employed by private contractors, a team of four workers can dig about a ton of coal a day, for which they earn around $10 to be split between them. The coalmine is in the heart of Punjab, Pakistan's most populous and richest province, but the labourers mostly come from the poorer neighbouring region of Khyber Pakhtunkhwa. (Photo by Sara Farid/Reuters)

A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

A giant new exhibition space created by famed graffiti artist Banksy opens to the public on May 3, 2008 in London, England. The disused tunnel beneath Waterloo station has been transformed by 30 artists from around the world. The three day event, tagged as the “Cans festival”, also invites the public to add their own stencil art. (Photo by Jim Dyson/Getty Images)

“On 24 July 2010, a stampede at the 2010 Love Parade electronic dance music festival in Duisburg, North Rhine-Westphalia, Germany, caused the death of 21 people. At least 510 more were injured”. – Wikipedia

Photo: Wall art and candles are pictured in the tunnel of the 2010 Loveparade disaster near to where many of the deaths occurred on the first anniversary of the tragedy on July 24, 2011 in Duisburg, Germany. (Photo by Thomas Starke/Getty Images)

A competitor scrambles in the mud under barbed wire during the Tough Guy Challenge 2009 at South Perton Farm on February 1, 2009 in Wolverhampton, England. The biannual event to raise cash for charity challenges thousands of international competitors to run through a gruelling set of 21 obstacles including water, fire and tunnels after a lengthy run at the start. (Photo by Christopher Furlong/Getty Images)

Chamrock, an Irish wolfhound, sports a green coat as he waits for the start of the St. Patrick's Day parade on March 17, 2012 in Chicago, Illinois. Tens of thousands took advantage of record high temperatures and sunny weather to attend the city's annual St. Patrick's Day celebration. (Photo by Brian Kersey/Getty Images)

A girl rides a broomstick in front of a green screen at the new Harry Potter Studio Tour at Warner Brothers Leavesden Studios on March 23, 2012 in London, England. The studio, which includes the actual sets and special effects departments where the films were created and shot, goes on public display on March 31, 2012. (Photo by Dan Kitwood/Getty Images)