An invited guest enjoys a private listening experience of a test unit of the Sennheiser HE 1 sound system, which is expected to retail for about S$77370 ($55000), in a hotel suite during the CanJam headphone and personal audio expo in Singapore February 21, 2016. (Photo by Edgar Su/Reuters)

A U.S. Army crew chief flying on board a CH-47F Chinook helicopter observes the successful test of flares during a training flight in Afghanistan, March 14, 2018. (Photo by Tech. Sgt. Gregory Brook/Reuters/U.S. Air Force)

“APOPO’s Training Center, situated on Sokoine Univeristy of Agriculture (SUA) in Tanzania, was established in 2000 to accommodate training and testing of mine detection rats in near-to-real conditions”. – APOPO

Photo: MDR (Mine Detection Rat) learn to look for mines. (Photo by APOPO's HeroRATs)

“Felix Baumgartner (born 20 April 1969 in Salzburg, Austria) is a skydiver and a BASE jumper. He is renowned for the particularly dangerous nature of the stunts he has performed during his career. Baumgartner spent time in the Austrian military where he practiced parachute jumping, including training to land on small target zones”. – Wikipedia

Photo: Pilot Felix Baumgartner of Austria is seen before his jump during the first manned test flight for Red Bull Stratos on March 15, 2012 in Roswell, New Mexico. In this test he reach the altitude 21800 meters (71500 ft) and landed safely near Roswell. Red Bull Stratos is a mission to the edge of the earths atmosphere, where upon reaching altitude of 120,000 feet by helium baloon, pilot and basejumper Felix Baumgartner will then freefall to the ground in an attempt to break the speed of sound. (Photo by Jay Nemeth/Red Bull via Getty Images)

Members of the Jordanian police women's team attend the 7th Annual Warrior Competition at the King Abdullah Special Operations Training Center in Amman April 22, 2015. Thirty-eight teams from 18 countries are participating in the competition to test their military skills. (Photo by Muhammad Hamed/Reuters)

A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)

A Chesterfield Borough Police telephone operator tests a gasmask with built in earpiece and microphone. The telephone service is considered one of the most important links in the coordination of ARP operations and must remain operational during air raids, 12th April 1939. (Photo by Fox Photos/Hulton Archive/Getty Images)

Peter Weiss, director of the Space Department of COMEX, (c) tests a pressurized suit identical to those used in space expeditions in the lava tunnel of “Caverne Gendarme” on October 12, 2018 in Saint-Philippe, the French overseas island of Reunion. Reunion could become a training site for astronauts. (Photo by Richard Bouhet/AFP Photo)