Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

Two people sit in an ambulance waiting to be treated after a Grad rocket slammed into a shopping mall in Donetsk's Kubishevski district, in the eastern Ukraine, on October 8, 2014. At least two people were killed, and five were injured after some six Grad rockets hit the area. (Photo by John Macdougall/AFP Photo)

Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

Festival-goers enjoy a fairground ride at Reading Festival in Reading, west of London, on August 27, 2021. As coronavirus covid-19 infection levels rise across the country, vaccines will be offered to revellers throughout the weekend. The organiser of Reading and Leeds Festivals has said such events are arguably “safer places to be” because attendees have been tested for covid-19. The festivals are returning this year with headliners including Stormzy, after being cancelled last year due to the pandemic. (Photo by Daniel Leal-Olivas/AFP Photo)

This watering hole is the social hub of the veldt; the scrubby grasslands that stretch across Namibia. The scorched earth supports sometimes fragile populations of magnificent wildlife – from endangered predators to plentiful herds of game. But these gentle giraffes and elephants need to be careful: lions don’t sleep at night, they hunt! The spectacular starscape above southern Africa is unchanged since explorers first mapped the continent. The photographer, Pietro Olivetta from Italy, said he had to be patient to capture these shots – but it was worth the wait. (Photo by Pietro Olivetta/Caters News)

A Sotheby's employee poses with a “Return of the Jedi” promotional C-3PO Helmet 1983, estimated at £15,000-£25,000 created by George Lucas' visual effects company during a photocall at Sotheby's in London, Britain on December 6, 2019. (Photo by Thomas Mukoya/Reuters)

Dolly the Chihuahua dog dressed as Alice in Wonderland is photographed during an Alice in Wonderland and Charlie and the Chocolate Factory themed Furbabies Dog Pageant at Jodhpurs Riding School in Tockwith, North Yorkshire, Sunday September 6, 2020. (Photo by Danny Lawson/PA Wire via AP Photo)

A woman looks on December 10, 2020 at a metal monolith that has popped up on a riverbank of the Vistula in the Polish capital Warsaw, the latest in a string of similar objects that have recently appeared in Europe and the US. Similar-looking objects were found in the United States, Romania and Britain. (Photo by Wojtek Radwanski/AFP Photo)