A weeping South Vietnamese mother and her three children are shown on the deck of this amphibious command ship being plucked out of Saigon by U.S. Marine helicopters in Vietnam, April 29, 1975. (Photo by AP Photo)

A sun bear reacts to triple-digit temperatures at the Henry Doorly Zoo in Omaha, Nebraska, where the temperature reached 103 degrees Fahrenheit on July 6, 2012. (Photo by Nati Harnik/Associated Press)

Guanacos sit during a signing ceremony in Patagonia Park, Chile, January 29, 2018. Chilean President Michelle Bachelet signed decrees Monday creating vast new national parks using lands donated by U.S. conservation organization Tompkins Conservation in what is believed to be the largest private donation of land ever from a private entity to a country. (Photo by Esteban Felix/AP Photo)

Rescue operations are undergoing to recover the sunken ferry MV Miraj 4 in the Megna River near Munshiganj, Bangladesh, 16 May 2014. The death toll in the Bangladesh ferry disaster rose to 26 on 16 May, including children and women and many more feared dead as the ferry, carrying more than 200 passengers on board, sunk during a storm on 15 may 2014, police authorities said. (Photo by Abir Abdullah/EPA)

Mia Sanford, graduating from Dr. Michael M. Krop Senior High School, takes a selfie picture with friends before participating in a parade of vehicles celebrating the graduating 2020 High School seniors on May 14, 2020 in Aventura, Florida. The graduating seniors were cheered on as they drove through the city escorted by the Aventura Police Department, students and parents. The unorthodox graduation ceremony was created as a way to safely celebrate during the coronavirus pandemic. (Photo by Joe Raedle/Getty Images)

20-year-old women visit the the Meiji shrine in Tokyo, Japan to celebrate Japan's Coming of Age Day on January 6, 2017. (Photo by Aflo/Rex Features/Shutterstock)

In this photo taken on Saturday, January 26, 2019 photo, rescued flamingo chicks have access to water at a centre after being rescued from a dried out dam in Kimberley, South Africa. A special airlift for thousands of baby flamingos is under way in South Africa as drought has put their breeding ground in peril. A reservoir that hosts one of southern Africa's largest flamingo populations is drying up. (Photo by AP Photo/Stringer)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)