Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

Mike “The Bedfordshire Bull Botteley” (left) takes on Chris “The General” Levy during a Chessboxing bout at the Scala nightclub on March 10, 2012 in London, England. A new hybrid sport combining chess and boxing in alternate 3 minute rounds, the winner is the one who knocks out or checkmates their opponent first. (Photo by Matthew Lloyd/Getty Images)

Looking towards the Times Building on Times Square, the Paramount Building is on the right, and Seventh Avenue on the left crossing Broadway. (Photo by General Photographic Agency/Getty Images). Circa 1930

Dan Pauly is a fourth generation wood-working artisan best known for his amazing rustic cabins made from reclaimed wood. The Minnesota-based craftsman builds saunas, sheds, bunkies and outhouses with his signature roof and chimney.

A Munduruku Indian child is pictured at the Planalto Palace, where a meeting with Minister of the General Secretariat of the Presidency of Brazil Gilberto Carvalho was being held with other Munduruku Indians, in Brasilia, June 4, 2013. President Dilma Rousseff's government sought on Tuesday to defuse mounting conflicts with indigenous groups over its decision to stop setting aside farm land for Indians and plans to build more hydroelectric dams in the Amazon. The government flew 144 Munduruku Indians to Brasilia for talks to end a week-long occupation of the controversial Belo Monte dam on the Xingu river, a huge project aimed at feeding Brazil's fast-growing demand for electricity. (Photo by Ueslei Marcelino/Reuters)

A general view showing the shipwrecked cruise ship Costa Concordia in an upright position after the salvage operations in Giglio island, Italy, 17 September 2013. Salvage crews pulled off a major engineering feat when they straightened the listed Costa Concordia cruise ship from the rocks it had been wedged against for the past 20 months. The delicate operation took 19 hours and was completed at 4 am (0200 GMT). The vessel ran aground near the island of Giglio, in Tuscany, in an accident that made world-wide news. (Photo by Angelo Carconi/EPA)

Developed for the British American Ambulance Corps, this new motorcycle ambulance is capable of speeding wounded soldiers 90 miles an hour from the front lines to field hospitals. Its springs are synchronized with the patient's heartbeat to avoid increasing fever when traveling over various Terrain. Viewing it in New York August 27, 1941, are left to right: constable Herbert Scott of England, driver; William E. Detlor, whose firm developed the vehicle; M. W. Stand, inspector-general of Civilian Defense, and Maj. Edward Riekert, also. (Photo by AP Photo)

A mascot of the Philippine National Police (PNP), named after their Chief Director General Ronald Dela Rosa, marches with members of the K9 units and the Special Action Force before the mass blessing for rescue dogs during the celebration of the feast day of St. Francis of Assisi, patron Saint of Animals, at the St. John Paul II parish church in Eastwood, Quezon city, metro Manila, Philippines October 2, 2016. (Photo by Romeo Ranoco/Reuters)