An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

A P-51 Mustang named “Charlotte's Chariot” from the Southern Heritage Air Foundation flies past a cloud of smoke and fire from a nearby battle reenactment during the Wings Over Houston Airshow in Houston, on Saturday, November 1, 2014. Battle reenactments are part of the yearly show held at Ellington Airport. (Photo by Kar Hlava/AP Photo/Bay Area Citizen)

People participate in a pillow fight to mark International Pillow Fight Day in the Heroes' Square, in central Budapest, Hungary, Saturday, April 2, 2016. The Pillow Fight Day attracts tens of thousands people in more than 100 cities all over the World each year. ((Photo by Zoltan Balogh/MTI via AP Photo)

Female soldiers march during a military parade marking the country's Independence Day in Caracas, Venezuela, Wednesday, July 5, 2017. Venezuela is marking 206 years of their declaration of independence from Spain. (Photo by Ariana Cubillos/AP Photos)

Emma Coburn (L) and Colleen Quigley of the U.S. look at the scoreboard after competing in the women's 3,000 metres steeplechase final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 26, 2015. (Photo by David Gray/Reuters)

A performer is seen floating in mid-air as he holds onto a moving bus during the International Magic Festival in Luoyang, Henan province, China September 11, 2016. (Photo by Reuters/China Daily)

After eight tense days, a female one horned rhinoceros was found and rescued from an area in India that has recently seen four other rhinos killed by poachers.

Photo: The rhino was finally located on Sunday in a field where it had taken shelter. Forest officials guarded the female one horned rhinoceros until it could be tranquilized and transported back to the Pobitora Wildlife Sanctuary. (Photo by Anupam Nath/Associated Press)

“A small British company with a dream of building a re-usable space plane has won an important endorsement from the European Space Agency (ESA) after completing key tests on its novel engine technology. Reaction Engines Ltd believes its Sabre engine, which would operate like a jet engine in the atmosphere and a rocket in space, could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away”. – Chris Wickham via Reuters. Photo: Artist's impression of Skylon. (Photo by Reaction Engines Ltd)