Blacksmith Johann Schmidberger works on a suit of armour for the Vatican's Swiss Guards at his workshop in Molln, Austria, March 29, 2017. Austrian blacksmiths who produce ceremonial suits of armour for the Vatican's Swiss Guards are close to the end of their current deal to do so, and say supplying the suits will not now be an issue for many years to come. One of the drawbacks of the Swiss Guards' medieval uniforms is that the craftsmanship needed to make them is disappearing. (Photo by Leonhard Foeger/Reuters)

Alfred Yetta (L) and Kay Manning pose for a photo in front of a cardboard cut-out of Pope Francis, during an event organised by Christa Scalies, the co-creator of the Pop-Up Pope, in Fado Irish Pub & Restaurant in Philadelphia, Pennsylvania, September 16, 2015. (Photo by Mark Makela/Reuters)

Look at the image for long enough and you can make the train change direction simply by thinking about it. Freaky.

Workers carry a rope line to fasten a decommissioned ship at the Alang shipyard in the western Indian state of Gujarat, March 27, 2015. The European Union plans to impose strict new rules on how companies scrap old tankers and cruise liners, run aground and dismantled on beaches in South Asia. However the practice in India, Bangladesh and Pakistan, hazardous for humans and the environment, will still be hard to stop. European, Turkish and Chinese recyclers are set to benefit from the revamped standards. Depending on raw material prices, ship owners can make up to $500 per tonne of steel from an Indian yard, compared with $300 in China and just $150 in Europe. (Photo by Amit Dave/Reuters)

A dog dressed as a Zoltar fortune telling machine participates in the Halloween Dog Parade in New York. (Photo by Timothy Clary/Getty Images)

These incredible pictures look like a bird's-eye view of a faraway alien planet – but they're actually hot springs. The amazing snaps are up-close shots of Iceland's hot springs, and the point-blank pictures produce a breathtaking array of colors and effects. Here: The amazing snaps are up-close shots of Icelandic hot springs. (Photo by Johann Vilhjalmsson/Caters News)

A stunning photographic collection featuring portraits of people from 30 countries and the food they eat in one day. In this fascinating study of people and their diets, 80 profiles are organized by the total number of calories each person puts away in a day. Featuring a Japanese sumo wrestler, a Massai herdswoman, world-renowned Spanish chef Ferran Adria, an American competitive eater, and more, these compulsively readable personal stories also include demographic particulars, including age, activity level, height, and weight. Essays from Harvard primatologist Richard Wrangham, journalist Michael Pollan, and others discuss the implications of our modern diets for our health and for the planet. This compelling blend of photography and investigative reportage expands our understanding of the complex relationships among individuals, culture, and food.

Participants dressed as Vikings carry torches as they march in procession before burning their viking galley ship at the culmination of the annual Up Helly Aa festival in Lerwick, Shetland Islands, on January 31, 2017. (Photo by Andy Buchanan/AFP Photo)