Members of the Bolivarian National Guard who joined Venezuelan opposition leader and self-proclaimed acting president Juan Guaido fire into the air to repel forces loyal to President Nicolas Maduro who arrived to disperse a demonstration near La Carlota military base in Caracas on April 30, 2019. Guaido – accused by the government of attempting a coup Tuesday – said there was “no turning back” in his attempt to oust President Nicolas Maduro from power. (Photo by Federico Parra/AFP Photo)

A Balinese Hindu blows fire, during a parade carrying Ogoh-ogoh effigies symbolising evil spirits, during a ritual before Nyepi, the day of silence, in Palembang, South Sumatra province, Indonesia March 8, 2016. Nyepi is a day of silence for self-reflection celebrating the Balinese Hindu new year, where people may not use lights, light fires, work, travel nor enjoy entertainment. (Photo by Darren Whiteside/Reuters)

Fighters Holly “The Lotus” Mei (L) and Teri “Feisty Fists” London train for the upcoming 'Lingerie Fighting Championships 22: Costume Brawl I' at DXG Self Defense on October 25, 2016 in Las Vegas, Nevada. The event is scheduled to feature eight bouts at 4 Bears Casino & Lodge on October 29, 2016 in New Town, North Dakota. (Photo by Ethan Miller/Getty Images)

Bryan Berg was introduced to card-stacking by his grandfather at the age of 8. He is a self-taught artist in all of the techniques he uses today. Berg's freestanding card structures are based on a grid-like arrangement, which Berg tested in a structural engineering lab to support 660 lbs per square foot―using no tape, no glue, no folding, and no tricks.

“Rivers Forgotten” is a journey through the passages and portals of the underground waterways that lie unseen below cities. Self-taught photographer Jeremy Kai brings these forgotten landscapes to light. Photo: Beneath the Toronto area, 2011. (Photo by Jeremy Kai)

The first load of passengers queuing for the Bennie Railplane in Glasgow; the inventor George Bennie is third in the queue. The streamlined cars are self propelled, driven by air screws in front and behind, and hang from a steel girder. (Photo by J. A. Hampton/Topical Press Agency/Getty Images). 4th July 1930

U.S. soldiers from 145th Field Artillery Battalion deployed from the United States fire Paladin self propelled gun during the Foal Eagle training exercise at firing point 180 at the Rodriguez Live Fire Range on March 15, 2012 in Pocheon, South Korea. (Photo by Chung Sung-Jun/Getty Images)

A 2S5 Giatsint self- propelled gun fires during tactical exercises held by artillery detachments of the Russian Eastern Military District' s 5th Army at the Sergeyevsky training ground in Primorye Territory, Russia on March 21, 2017. Over 2500 servicemen practice combat skills received in 2017 winter training exercises. (Photo by Yuri Smityuk/TASS)