In this March 14, 2015 photo, tourists take pictures from a viewing area at Iguazu Falls in Brazil. From walkways and bridges, viewers can count 270 water falls almost 100 meters (330 feet) high. (Photo by Jorge Saenz/AP Photo)

People look at a vehicle at the “Salon Prive” luxury and supercar event on June 22, 2011 in London, England. The annual three day Salon Prive offers the opportunity to view the most exotic modern and vintage super cars in the world and is being held for the first time at Syon Park. (Photo by Dan Kitwood/Getty Images)

The space shuttle Atlantis lifts off from launch pad 39A at the Kennedy Space Center in Cape Canaveral, Florida May 14, 2010. (Photo by Pierre Ducharme/Reuters)

One-day-old baby giraffe calf Gus looks at the camera at Noah's Ark farm on May 12, 2017 in Bristol, England. The baby giraffe was born yesterday at the zoo farm in North Somerset. In the wild, populations of giraffes are suffering from a continuing decline, with 97,500 estimated in Africa in 2015. Since 1985 the total giraffe population has fallen by 35%. New arrival Gus joins brothers George, 4 and Geoffrey, 2. (Photo by Matt Cardy/Getty Images)

A girl watches an acrobatic performance at the Longtan park as the Chinese Lunar New Year, which welcomes the Year of the Monkey, is celebrated in Beijing, China February 9, 2016. (Photo by Damir Sagolj/Reuters)

In this July 15, 2015 photo, Nepalese amputee victims Khendo Tamang, left, and Nirmala Pariyar, both 8, share a single pair of shoes at the Bir Trauma Center in Kathmandu, Nepal. After suffering serious leg wounds in Nepal's massive 2015 earthquake that killed and injured thousands, both girls were brought to the Bir Trauma Center in Kathmandu, to receive single leg amputations. Following their surgeries, Nirmala's relentless cheerfulness drew a still very depressed Khendo close and both found an inseparable friendship which has helped their emotional wounds heal. (Photo by Niranjan Shrestha/AP Photo)

A worker unloads fish from a taxi boot at a fish market in Kolkata, India on February 5, 2018. (Photo by Rupak De Chowdhuri/Reuters)

An aerial view shows a Russian Troika, a sledge drawn by three horses, competing on the ice-covered Yenisei River during the annual Ice Derby amateur horse race near the Siberian settlement of Novosyolovo, south of Krasnoyarsk, Russia March 17, 2018. (Photo by Ilya Naymushin/Reuters)