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)

Party-goers partake in a festival better known as Holi One, during International Workers Day in Johannesburg, South Africa, 01 May 2015. The colour festival promotes togetherness as well as colourness in everday life. May Day is observed worldwide every year on 01 May. (Photo by Kevin Sutherland/EPA)

A man wears a protective face mask on a street, amid the spread of the coronavirus disease (COVID-19), in Bangkok, Thailand, August 21, 2020. (Photo by Jorge Silva/Reuters)

Fireworks are seen above the Washington Monument and the White House at the conclusion of the final day of the Republican National Convention on August 27, 2020 in Washington, DC. President Donald Trump and Vice President Mike Pence accepted the nomination as the Republican candidates for a second term in the White House. (Photo by Tasos Katopodis/Getty Images)

A schoolgirl stands next to the Kenya-Uganda railway line during the partial reopening of schools, after the government scrapped plans to cancel the academic year due to the coronavirus disease (COVID-19) pandemic, in Kibera slums of Nairobi, Kenya on October 12, 2020. (Photo by Thomas Mukoya/Reuters)

Local folk artists perform next to a police line outside Congress building, as they wait for news from inside on who will be the country's next president, in Lima, Peru, Sunday, November 15, 2020. Interim President Manuel Merino announced his resignation following massive protests unleashed when lawmakers ousted President Martin Vizcarra. (Photo by Rodrigo Abd/AP Photo)

A person falls down stairs while sledding in Central Park as snow falls in Manhattan, New York City, U.S., February 7, 2021. (Photo by Andrew Kelly/Reuters)

Rope access technicians carry out maintenance service on wind turbines including repairs, blade inspections and cleaning in Izmir, Turkey on February 19, 2021. In Turkey, where investments in renewable energy has increased, there are wind tribunes over 3,500. (Photo by Mahmut Serdar Alakus/Anadolu Agency via Getty Images)