Dharma the Sumatran tiger yawns as members of the public return to Edinburgh Zoo as it opens for the first time following the easing of Scottish Governments lockdown restrictions on June 29, 2020 in Edinburgh, Scotland. Outdoor visitor attractions in Scotland have reopened along with many non-essential retailers after more than three months in lockdown, as Scotland moves into phase 2 of its “route map” for easing coronavirus restrictions. (Photo by Jeff J. Mitchell/Getty Images)

In this January 27, 2015 photo, penguins walk on the shore of Bahia Almirantazgo in Antarctica. Antarctica “is big and it's changing and it affects the rest of the planet and we can't afford to ignore what's going on down there”, said David Vaughan, science director of the British Antarctic Survey. (Photo by Natacha Pisarenko/AP Photo)

The Blue Man Group performs on stage during a media preview ahead of their show in Singapore on March 31, 2016. Blue Man Group was started by three friends in New York in 1991 as a way to celebrate the human spirit through music, science, art and theater. (Photo by Roslan Rahman/AFP Photo)

A woman takes a selfie with “RoboThespian” at Robots, a major new exhibition at Science Museum in London, England on February 7, 2017. Exhibition showcases 500-year history of robots, with over 100 robots and the largest collection of humanoid robots ever displayed. (Photo by Tolga Akmen/Anadolu Agency/Getty Images)

Fans dressed in Spider-Man outfits gather at a promotional event for the forthcoming “Spider-Man: Homecoming” movie at the Art Science Museum in Singapore on June 7, 2017. The movie will be shown in cinemas around the world from July 5 onwards. (Photo by Toh Ting Wei/AFP Photo)

This photograph taken during a government organised media tour shows College of Science graduates from Tibet University celebrating their graduation at the Potala Palace Square in the regional capital Lhasa, in China's Tibet Autonomous Region, on June 1, 2021. (Photo by Hector Retamal/AFP Photo)

People enjoy the fine weather on the coast at Wembury during the first ever nationwide survey to map the location of the threatened and creatures on March 24, 2011 in near Plymouth, England. Often found on the coast, and particularly in the south west of England, the number of oil beetle species found in the UK has halved in the last 100 years and the survey will help establish the whereabouts of the remaining four species and boost efforts to secure their future. The survey is being launched today by Buglife: The Invertebrate Trust and the National Trust in partnership with Natural England and Oxford University Museum of Natural History. (Photo by Matt Cardy/Getty Images)

The Grand Canyon Skywalk is a transparent horseshoe-shaped cantilever bridge and tourist attraction in Arizona near the Colorado River on the edge of a side canyon in the Grand Canyon West area of the main canyon. USGS topographic maps show the elevation at the Skywalk's location as 4,770 ft (1,450 m) and the elevation of the Colorado River in the base of the canyon as 1,160 ft (350 m), and they show that the height of the precisely vertical drop directly under the skywalk is between 500 ft (150 m) and 800 ft (240 m).