U.S. soldiers from the 3rd Cavalry Regiment take part in an artillery exercise on forward operating base Gamberi in the Laghman province of Afghanistan December 24, 2014. (Photo by Lucas Jackson/Reuters)

Three-month old cheetah cubs make their public debut at the Smithsonian National Zoo on July 24, 2012 in Washington, DC. (Photo by T.J. Kirkpatrick)

Urban photographer Roman Robroek spent five years scouring the continent for the grandest examples of forgotten architectural beauty. Here: Watch your step on this Polish spiral staircase. (Photo by Roman Robroek/South West News Service)

Mulan Jamilah, a 6-year-old Bengal tiger and Abdullah Sholeh, 33, play in the garden beside their home on January 20, 2014 in Malang, Indonesia. Abdullah Sholeh of Malang, Indonesia is an Islamic student who has become best friend and a full-time nanny to the tiger.

Russian honor guard soldiers warm up prior a rehearsal for the Victory Day military parade in St. Petersburg, Russia, Wednesday, May 3, 2017. The parade will take place at Dvortsovaya (Palace) Square on May 9, to celebrate 72 years after the victory in WWII. (Photo by Dmitri Lovetsky/AP Photo)

Against the scorching sun, a hungry jackal chases a flock of birds looking for a quick morning snack. Taken in South Africa's Kgalagadi Transfrontier National Park, these images capture the moment a lone hunter tries, and then succeeds, in his pursuit. (Photo by John Mullineux/Solent News)

Women walk in heavy rain as Typhoon Haishen hits Kagoshima, Kagoshima prefecture on September 6, 2020. Typhoon Haishen began to lash southern Japan on September 6, with officials warning it could bring record rainfall and winds strong enough to snap power line poles and flip cars. (Photo by Charly Triballeau/AFP Photo)

A woman wearing a face mask walk through Shinjuku area on January 07, 2021 in Tokyo, Japan. Japanese Prime Minister Yoshihide Suga is set to declare a state of emergency in Tokyo and neighboring three prefectures, Kanagawa, Saitama, and Chiba on Thursday, following the recent surge in COVID-19 cases in the region. Tokyo saw over 2000 new cases per day for the first time on January 7, 2021. (Photo by Yuichi Yamazaki/Getty Images)