Members of the 1st Tennessee wait to take part in in a demonstration of a battle during ongoing activities commemorating the 150th anniversary of the Battle of Gettysburg, Friday, June 28, 2013, at at Bushey Farm in Gettysburg, Pa. Union forces turned away a Confederate advance in the pivotal battle of the Civil War fought July 1-3, 1863, which was also the war's bloodiest conflict with more than 51,000 casualties. (Photo by Matt Rourke/AP Photo)

The jewelled flower mantis, commonly found in Asia, is believed to be the inspiration for many martial artists is seen in Jakarta, Indonesia on August 2, 2016. (Photo by Prabu Dennaga/Barcroft Images)

The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)

Naked riders seen participating during the World Naked Bike Ride to demonstrate the vulnerability of cyclists on city streets in London, United Kingdom on June 9, 2018. People chose to ride naked to celebrate cycling and body freedom. (Photo by Brais G. Rouco/SOPA Images/LightRocket via Getty Images)

People gather on a hill near the Chopin Airport to watch aeroplanes taking off, in Warsaw, Poland, Sunday, September 9, 2018. (Photo by Alik Keplicz/AP Photo)

Aerial view over mud and waste from the disaster caused by dam spill in Brumadinho, Minas Gerais, Brazil, 26 January 2019. At least nine people have died and 300 are missing after a tailings dam burst at the Feijao mine in southeastern Brazil owned by Vale, the world's largest iron-ore producer, the Minas Gerais state government said. The dam in Brumadinho near Belo Horizonte broke on 25 January at around mid-day, unleashing a river of sludge that destroyed some nearby houses. (Photo by Antonio Lacerda/EPA/EFE)

Fans and community members gather around a LAPD car along the procession route for Nipsey Hussle after his memorial at the Staples Center in Los Angeles, California, April 11, 2019. 4 people shot and 1 dead during the procession LAPD reported on late April 11, 2019 The Grammy-nominated artist was killed in front of The Marathon Clothing store he founded in 2017. (Photo by Kyle Grillot/AFP Photo)