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)

In this November 3, 2015 file photo, Afghan Taliban fighters listen to Mullah Mohammed Rasool, the newly-elected leader of a breakaway faction of the Taliban, in Farah province, Afghanistan. Despite US President Donald Trump’s pronouncement that there would be no talks with the Taliban following a series of deadly attacks in Kabul, officials say talks continue, but neither side trusts the other and neither believes the other negotiates independently. (Photo by AP Photo/Stringer)

Tourists kissing front of Malaysia's landmark Petronas Twin Towers with lights on before turned off to mark Earth Hour 2016 in Kuala Lumpur, Malaysia, 19 March 2016. Earth Hour takes place worldwide at 8.30 p.m. local time and is a global call to turn off lights for 60 minutes to raise awareness of the danger of global climatic change (Photo by Fazry Ismail/EPA)

Rohingya refugees stand outside of their refugee camp on February 11, 2017 in Medan, North Sumatra, Indonesia. Thousands of Rohingya Muslims have been stuck in limbo at Indonesia's refugee camps as the plight of Myanmar's ethnic minority continues. (Photo by Ulet Ifansasti/Getty Images)

Rita Ora strips down to promote the new Tezenis lingerie range on December 7, 2016. The British singer, 26, shows off her curves in the latest campaign for the Italian brand. (Photo by Splash News/Tezenis)

In this photo posted on Twitter, Sunday, May 3, 2015, and provided by NASA, Italian astronaut Samantha Cristoforetti sips espresso from a cup designed for use in zero-gravity, on the International Space Station. Cristoforetti, the first Italian woman in space, fired up the first espresso machine in space, which uses small capsules, or pods, of espresso coffee. (Photo by AP Photo/NASA)

A visitor takes photos of “Grecian Nude” by British artist Damien Hirst, as part of the exhibition “Archaeology Now” at Galleria Borghese in Rome on June 07, 2021. The exhibition, running through June 08 – November 07, 2021, features over 80 works from Hirst’s Treasures from the Wreck of the Unbelievable series, displayed throughout the museum alongside ancient masterpieces. (Photo by Tiziana Fabi/AFP Photo)

A peformance artist attends an election rally for Cameroon presidential candidate for the opposition Univers party, Cabral Libii in Yaounde, Cameroon 06 October 2018. Africa's oldest president Paul Biya who has been in power since 1982 is up against eight candidates when voters go to the polls 07 October 2018. 6.9 million registered voters will head to the polls but marginalised anglophone separatists in the North West and South West of the country threaten to disrupt the elections. (Photo by Nic Bothma/EPA/EFE)