Slovenian photographer Peter Gedei started caving 25 years ago and has carried a camera with him on every trip getting stunning pictures from his travels, capturing the ice formations, tight chambers and beautiful halls. Photo: The Ice Cave in Postojna, Slovenia. (Photo by Peter Gedei/Caters News)

Members of the Pontifical Swiss Guard stand by at St. Peter's Square before Pope Francis delivers his traditional Christmas Day Urbi et Orbi speech to the city and the world from the main balcony of St. Peter's Basilica at the Vatican, December 25, 2021. (Photo by Yara Nardi/Reuters)

Colorado Gov. John Hickenlooper shows off his socks--one with Democratic presidential candidate Bernie Sanders and the other with Republican candidate Donald Trump – before entering his former brewpub for a book signing event to mark the release of his autobiography Thursday, May 26, 2016, in Denver. Hickenlooper, who is term-limited, is doing book talk rounds this week, reviving speculation that he is positioning himself to join Hillary Clinton's presidential campaign ticket. (Photo by David Zalubowski/AP Photo)

Very impressive, the RGB Colorspace Atlas is a beautiful picture book by American artist Tauba Auerbach. The book displays the full RGB gradient in 3,632 pages.

The competition is run by Royal Observatory Greenwich sponsored by Insight Investment and in association with BBC Sky at Night Magazine. This year astrophotographers from 91 countries sent in more than 4,200 spectacular entries. Here: The Milky Way rises above an isolated lighthouse in Tasmania. Shot by James Stone of Australia. (Photo by James Stone/Astronomy Photographer of the Year 2018)

A lone male cheetah is set upon by a pack of African wild dogs. Peter Haygarth had been following the dogs as they hunted in Zimanga Private Game Reserve in KwaZulu-Natal, South Africa. On first encountering the cheetah, the dogs were wary, but as the rest of the pack arrived, their confidence grew and they began to encircle the cat. Peter kept his focus on the cat’s face. In a few minutes the spat was over as the cheetah fled. (Behaviour: mammals category). (Photo by Peter Haygarth)

“Guns have a massive amount of power associated with them. They are designed to kill. We decided to photograph portraits of them in a similar way you might photograph a powerful person. Like powerful people, pistols have this “perfect” quality that we wanted to explore. As we started shooting them, we could see flaws in their design. Metal burring around the barrels, scratches in the metal. This imperfection and detail were very interesting to us; connecting us back to these images as portraits”. – Peter Andrew. (Photo by Peter Andrew/Simon Duffy/Derek Blais)

Women dressed as nuns pose for pictures during Halloween celebrations in the Shibuya district in Tokyo, Japan October 31, 2015. (Photo by Thomas Peter/Reuters)