A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

Titanoboa, meaning "titanic boa," is an extinct genus of snake that lived approximately 60–58 million years ago, during the Paleocene epoch, a 10-million-year period immediately following the dinosaur extinction event. The only known species is Titanoboa cerrejonensis, the largest, longest, and heaviest snake ever discovered, which supplanted the previous record holder, Gigantophis.

A full-scale model of the snake was unveiled at New York City's Grand Central station before the exhibit opens at the Smithsonian in Washington DC.

This image made available by the Johns Hopkins University Applied Physics Laboratory on Wednesday, May 31, 2017 depicts NASA's Solar Probe Plus spacecraft approaching the sun. On Wednesday, NASA announced it will launch the probe in summer 2018 to explore the solar atmosphere. It will be subjected to brutal heat and radiation like no other man-made structure before. (Photo by Johns Hopkins University Applied Physics Laboratory via AP Photo)

ESA astronaut Tim Peake posted this stunning image on his social media channels, commenting: “Station passed through magnificent aurora Australis last night”. Tim is set to return to Earth on 18 June 2016, bringing his six-month Principia mission to the ISS to an end. During his stay he performed more than 30 scientific experiments for ESA and taking part in numerous others from ESA's international partners. ESA and the UK Space Agency have partnered to develop many exciting educational activities around the Principia mission, aimed at sparking the interest of young children in science and space. (Photo by Tim Peake/ESA/NASA)

An image produced by the Hubble telescope of the perfectly “edge-on” galaxy, or NGC 4013, March 1, 2001. This new Hubble picture reveals, with great detail, huge clouds of dust and gas extending along, as well as far above, the galaxy's main disk. NGC 4013 is a spiral galaxy, similar to the Milky Way, lying some 55 million light-years from Earth in the direction of the constellation Ursa Major. Viewed face-on, it would look like a nearly circular pinwheel, but NGC 4013 happens to be seen edge-on from our vantage point. Even at 55 million light-years, the galaxy is larger than Hubble's field of view, and the image shows only a little more than half of the object, albeit with unprecedented detail. (Photo Courtesy of NASA/Newsmakers)

A coil-shaped Helix Nebula showing a fine web of filamentary “bicycle-spoke” features embedded in the colorful red and blue ring of gas. At 650 light-years away, the Helix is one of the nearest planetary nebulae to Earth. A planetary nebula is the glowing gas around a dying, Sun-like star. (Photo by Reuters/NASA)

Winner – Animal Portraits: The pose by Mogens Trolle, Denmark. A young male proboscis monkey cocks his head slightly and closes his eyes. Unexpected pale blue eyelids now complement his immaculately groomed auburn hair. He poses for a few seconds as if in meditation. He is a wild visitor to the feeding station at Labuk Bay Proboscis Monkey Sanctuary in Sabah, Borneo – “the most laid-back character”, says Trolle, “quite unlike anything I’ve ever seen on another monkey” – connects us, he hopes, with a fellow primate. (Photo by Mogens Trolle/Wildlife Photographer of the Year 2020)

A mural depicting a resting cat by Russian street artist Vladi is photographed by a man outside a hotel in Hong Kong on November 27, 2023. (Photo by Peter Parks/AFP Photo)