A masked reveller parades through the streets on the first day of the carnival season in Lucerne, Switzerland, 12 February 2015. In the background the well known Kappellbruecke bridge. (Photo by Alexandra Wey/EPA)

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)

A machine works on a Rio 2016 Olympic medal at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. The Casa da Moeda do Brasil is the Brazilian mint, owned by the Brazilian government and administratively subordinated to the Ministry of Finances. It was established in 1694. (Photo by Sergio Moraes/Reuters)

Class of 2027 plebes climb during the Herndon Monument Climb at the U.S. Naval Academy, Wednesday, May 15, 2024, in Annapolis, Md. Freshmen, known as Plebes, participate in the climb to celebrate finishing their first year at the academy. The climb was completed in two hours, nineteen minsters and eleven seconds to complete. (Photo by Tom Brenner/AP Photo)

The Blue Man Group performs on stage during a media preview ahead of their show in Singapore on March 31, 2016. Blue Man Group was started by three friends in New York in 1991 as a way to celebrate the human spirit through music, science, art and theater. (Photo by Roslan Rahman/AFP Photo)

Members of the “Exit Point” amateur rope-jumping group jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, September 13, 2015. Rope-jumping, an extreme sport, involves jumping from a high point using an advanced leverage system combining mountaineering and rope safety equipment. (Photo by Ilya Naymushin/Reuters)

Young women pose for photos in a Christmas-themed tunnel lit-up with decorations outside a shopping mall in Bangkok on December 4, 2020. (Photo by Mladen Antonov/AFP Photo)

A little girl takes a picture of a lion in the zoo in Frankfurt, Germany, Tuesday, September 13, 2016. (Photo by Michael Probst/AP Photo)