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)

Four young, trendsetting architectural offices from Denmark, Holland and France along with PensionDenmark are the clever ones behind the Iceberg – a unique house building, sporting 11 pinnacles, situated at the outermost corner of Aarhus Harbour, thus having a spectacular view of Aarhus Bay and Kalø Cove and Aarhus City.

In this Tuesday, August 2, 2016 photo released by Xinhua News Agency, people stand on a platform as the Transit Elevated Bus TEB-1 conducting a test run after it unveiled in Qinhuangdao, north China's Hebei Province. The 72-feet long and 25-feet wide Transit Elevated Bus (TEB) powered by electricity can carry more than hundreds passengers, is designed to go over the normal traffic to help ease traffic congestion without having to dig new tunnels or build elevated rail tracks. (Photo by Luo Xiaoguang/Xinhua via AP Photo)

Hospitality staff members laugh as they stand on Tiananmen Square before the closing ceremony of China's 19th Party Congress at the Great Hall of the People in Beijing, Tuesday, October 24, 2017. The ruling Communist Party on Tuesday formally lifted Xi Jinping's status to China's most powerful ruler in decades, setting the stage for the authoritarian leader to tighten his grip over the country while pursuing an increasingly muscular foreign policy and military expansion. (Photo by Mark Schiefelbein/AP Photo)

Ramoncito Campo kisses his wife Hernelie Ruazol Campo on a flooded street during a southwest monsoon that battered Manila August 8, 2012. The newly-wed couple pushed through with their scheduled wedding despite severe flooding that inundated wide areas of the capital and nearby nine provinces. (Photo by Reuters/Courtesy of Ramoncito Campo)

Alfred the frog looks almost as scary as the pumpkin he is perched on at London Zoo 26 October 2011. Keepers at the zoo have joined in the Halloween tradition by supplying pumpkin lunches to some of their animals, including the giant waxy monkey frog. However Alfred is not quite the giant figure his species name suggests – he actually measures up at around 4 inches (10 centimeters). (Photo by EPA/Zoological Society of London)

A woman poses next to two mailboxes along a street in Taipei on August 11, 2015 that were reportedly bent by strong winds brought by Typhoon Soudelor over the weekend. The two iron mailboxes have become an unlikely attraction, drawing thousands of snap-happy visitors and have even become a backdrop to a wedding photo shoot. The typhoon, which hit in the early hours of August 8 and was billed as the most powerful typhoon this year, uprooted trees, brought down electricity poles, knocking out power to a record 4.3 million households, while leaving eight dead and four missing. (Photo by Benjamin Yeh/AFP Photo)

Culinary Specialist 2nd Class Jaqueline Rodriguez subdues a simulated suspect after being sprayed with oleoresin capsicum (OC) spray during security training aboard the amphibious dock landing ship USS Comstock (LSD 45). (U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac/Released). May 10, 2011