A hiker admires the view as Mt. Etna, Europe's largest active volcano, erupts in the background, in the Bove Valley of Etna Park, on the eastern slope of Mt. Etna, in Sicily, southern Italy, Sunday, July 4, 2021. Since Feb. 16, 2021, Mt. Etna has begun a series of eruptive episodes. (Photo by Salvatore Allegra/AP Photo)

The Tsaatan people are one of the world’s last groups of nomadic reindeer herders and they live in Khövsgöl Aimag in northern Mongolia. They are originally from across the border in what is now the Tuva republic of Russia. (Photo by Pascal Mannaerts/Rex Feature/Shutterstock)

Clouds gather as walkers pause atop a ridge in Mountain View, California January 7, 2016. (Photo by Noah Berger/Reuters)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

Snow falls as a woman walks her dog in the village of Podolye, 70 kilometers (43 miles) east of St. Petersburg, Russia, early Thursday, May 11, 2017. North winds brought snow to the east of the St. Petersburg region. (Photo by Dmitri Lovetsky/AP Photo)

Pokot men carry a part of a carcass of a bull killed by a young man during an initiation ceremony in Baringo County, Kenya, January 20, 2016. Far from the bustling city of Nairobi, in an isolated corner of Kenya's Rift Valley, young men from the Pokot community spear a bull in a ceremony called Sapana that takes them into adulthood. (Photo by Siegfried Modola/Reuters)

A man walks on the road between Nouahibou and Nouakchott, where three Spanish aid workers were abducted in Mauritania, December 3, 2009. (Photo by Rafael Marchante/Reuters)

A couple sunbath on the beach in Ostrowo, northern Poland, July 20, 2015. Picture taken July 20, 2015. (Photo by Kacper Pempel/Reuters)