Members of the “Avalon” team wearing 14th century knight costumes fight against each other on the bank of the Yenisei River during the regional amateurs tournament of clubs of historical reconstruction, “The Battle of the Nations 2015. Siberia”, in Krasnoyarsk January 24, 2015. (Photo by Ilya Naymushin/Reuters)

“Kids of Sapa”. Four little beautiful Hmong girls from Lao Chai Village, near Sapa, Vietnam. (Photo and caption by Felipe Hanower/National Geographic Traveler Photo Contest)

A visitor takes a photo of a boulder plastic made of synthetic material called “To be in Limbo” hangs from the ceiling of the 20 meter high Jesuit Church in Vienna, Austria, Tuesday, November 25, 2014. The eight meter high, hollow and 700 kilogram heavy sculpture from the artists group Steinbrener/Dempf and Huber is supposed to symbolize faith and its threatening moments. The installation will remain until April 19, 2015 and then move to a church in Hamburg, Germany. (Photo by Ronald Zak/AP Photo)

The 26th annual National Geographic Traveler Photo Contest is now accepting submissions. Official categories include: “Travel Portraits”, “Outdoor Scenes”, “Sense of Place” and “Spontaneous Moments”. The contest is accepting entries until June 30. Photo: “Forest lights”. Aurora Borealis over the forest of the Pyhae Luosto National Park, Finland. (Photo and caption by Nicholas Roemmelt/National Geographic Traveler Photo Contest)

Real life doll Alina Kovalevskaya poses for a photograph on May 29, 2014 in Odessa, Ukraine. Alina Kovalevskaya is a walking, talking, breathing living doll on the lookout for her real-life Ken. The 21-year-old is from Odessa, Ukraine – the same city as real-life Barbie Valeria Lukyanova, who has made headlines around the world for her unique look and controversial opinions. The pair were friends, but their relationship has since soured. Alina has made a splash online, with her YouTube videos showing off her doll-like charms attracting hundreds of thousands of views. (Photo by Aleksey Solodunov/Barcroft Media)

The proliferation of marijuana edibles for both medical and recreational purposes is giving rise to a cottage industry of baked goods, candies, infused oils, cookbooks and classes that promises a slow burn as more states legalize the practice and awareness spreads about the best ways to deliver the drug. Edibles and infused products such as snack bars, olive oils and tinctures popular with medical marijuana users have flourished into a gourmet market of chocolate truffles, whoopie pies and hard candies as Colorado and Washington legalized the recreational use of marijuana in the past year. Photo: In this Thursday, July 10, 2014, photo, Mike Fitzgerald, right, teaches behind a sample display of cannabis-infused products during a cooking class at the New England Grass Roots Institute in Quincy, Mass. (Photo by Michael Dwyer/AP Photo)

“Sidney D. Gamble (July 12, 1890 – 1968) was born in Cincinnati, Ohio, to David Berry and Mary Huggins Gamble; grandson of James Gamble, who, with William Procter, founded Procter & Gamble in 1837. in 1912 he graduated magna cum laude from Princeton University with a Bachelor of Literature degree and was elected to Phi Beta Kappa. He visited China for four extended periods, 1908, 1917–1919, 1924–27, and 1931–1932, doing Christian social work for the Y.M.C.A and conducting social surveys. He is now best known for his remarkable and extensive photographs of Peking and North China.” – Wikipedia. (Photo by Sidney David Gamble via Duke University Libraries)

Photo: Hillcoat Riding Fu Tu. China, An Xian, 1917-1919. P.S. All photos are available in high resolution.

Two women lighting cigarettes on a tennis court in Essex, England circa 1930's. (Photo by Keystone View/FPG/Getty Images)