Revellers attend the Saint Patrick's Day parade on March 17, 2019 in Dublin, Ireland. Saint Patrick, the patron saint of Ireland is celebrated around the world on St. Patrick's Day. According to legend Saint Patrick used the three-leaved shamrock to explain the Holy Trinity to Irish pagans in the 5th-century after becoming a Christian missionary. (Photo by Charles McQuillan/Getty Images)

The International Space Station (ISS) moves along its orbit above at the Russian leased Baikonur cosmodrome, Kazakhstan, Thursday, July 18, 2019, with a statue of Soviet Union founder Vladimir Lenin in the foreground. Circular star tracks around the Polar Star and tracks of the ISS is the result of the camera multiple exposure with a total duration of two hours. (Photo by Dmitri Lovetsky/AP Photo)

People walk along the Dune du Pilat (Dune of Pilat), the tallest sand dune in Europe, in La Teste de Buch, near Bordeaux, France, June 15, 2016. The dune has a volume of about 60,000,000 m³, measuring around 500 m wide from east to west and 2.7 km in length from north to south. Its height is currently 110 meters above sea level. (Photo by Sergio Perez/Reuters)

Aiden Haas, left, and Lilli Alcala pose after being crowned Mud King and Mud Queen at the 29th annual Mud Day, Tuesday, July 12, 2016 in Westland, Mich. The event, open to children 12 and younger, was at the Hines Park-Nankin Mills Area west of Detroit. Children 12 and younger were able to slosh around in the pit while participating in mud limbo, wheelbarrow races and other free activities. (Photo by Carlos Osorio/AP Photo)

Nepalese Hindu priests perform rituals during Janai Purnima festival at Pashupatinath temple in Kathmandu, Nepal, Thursday, August 18, 2016. During this festival Hindus take holy baths and perform annual change of the Janai, a sacred cotton string worn around their chest or tied on the wrist, in the belief that it will protect and purify them. (Photo by Niranjan Shrestha/AP Photo)

A tourist walks inside the Ice Palace glacier hollow at Hintertux glacier, located at around 3250 meters above sea level, in Zillertal, Austria, 02 March, 2016. The hollow's temperature remains constant at 0 degrees Celsius, in summer and winter alike, and is also used by the University of Innsbruck for scientific research projects. (Photo by Lisi Niesner/EPA)

Musher Justin Savidis' dogs wait in the truck before the restart of the Iditarod Trail Sled Dog Race in Willow, Alaska March 6, 2016. Mushers and dog sled teams from around the world embark on the first leg of Alaska's grueling Iditarod Trail Sled Dog Race, starting a nearly 1,000-mile (1,609 km) journey through the state's unforgiving wilderness. (Photo by Nathaniel Wilder/Reuters)

A hot air ball balloon floats past while people stand in line to climb the Pyramid of the Sun and welcome the spring equinox in the pre-hispanic city of Teotihuacan, on the outskirts of Mexico City, Mexico, March 20, 2016. Spring equinox in Teotihuacán is an annual event which takes place around the 20th and 21st of March at the pre-Hispanic site of Teotihuacán, Mexico. This event is mirrored by other similar events in other pre-Hispanic sites such as Chichén Itzá and Malinalco, Mexico State. (Photo by Edgard Garrido/Reuters)