Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)

The photographs feature fish that have been specially treated to make the stained skeletal tissues visible through the skin and flesh. The technique, developed by Dr. Adam Summers, uses dyes, hydrogen peroxide, a digestive enzyme and glycerin to make the flesh seem to disappear. Photo: This image of the butterfly ray (Gymnura crebripunctata) helped scientists study the joints in its wings. (Photo by Adam Summers)

A gaggle of goslings huddle together under the protective wing of a parent along the bank of the Deschutes River as a heavy downpour passes through Bend, Oregon, late Wednesday, April, 20, 2106 afternoon. (Photo by Ryan Brennecke/The Bulletin via AP Photo)

“Leopard Hunting a Stork”. “One-shot capture. I watched the leopard stalking the stork, I only had time to focus at 400mm, no time to change to high speed, I watched the stork, and as soon as it flapped its wings, I shot one shot”. (Photo by Paul Rifkin/National Geographic Travel Photographer of the Year Contest)

Wing maker Marian Hose (L), also known as “Killer”, and Model Martha Hunt take part in a fitting ahead of the Victoria's Secret fashion show in New York, U.S., October 30, 2018. (Photo by Kevin Coombs/Reuters)

A member of the Air Force's Wings of Blue Parachute Demonstration Team salutes as he jumps out of an aircraft, during the opening ceremony of Aviation Nation 2017 Nellis Air and Space Expo at Nellis Air Force Base, Nev., November 10, 2017. (Photo by Senior Airman Kevin Tanenbaum/Reuters/U.S. Air Force)

A Palestinian fighter from Ezz-Al Din Al-Qassam Brigades, the armed wing of the Hamas movement, checks debris at the site of an Israeli air strike in Khan Yunis in the southern Gaza Strip on December 26, 2019. (Photo by Said Khatib/AFP Photo)

A girl walks along former railway tracks in the so- called “Tunnel of Love”, surrounded by arches of intertwined trees, near the Ukrainian village of Klevan, Rivno region, on August 6, 2018. The tunnel of about five kilometres in length is a botanical phenomenon, which became a cult place for tourists and couples in love. The tourist legend says that wishes of couples in love will come true, if the couple passes through the tunnel. (Photo by Sergei Supinsky/AFP Photo)