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)

Mystical Forest. Tracey Jennings photographed this seven-gill shark in a kelp forest just off the shore of Simon's Town near Cape Town, South Africa. You don't need to travel far from cities to visit Narnia. This 7 gill shark was photographed in a kelp forest just off the shore of Simonstown near Cape Town, South Africa. (Photo by Tracey Jennings/National Geographic Travel Photographer of the Year Contest)

Girls in swimsuits participate in the Grelka Fest at the ski resort Sheregesh in Tashtagolsky District of Kemerovo Oblast, Russia on April 15, 2018. Skiers and snowboarders from around the world marked the end of the 2017-18 winter season. Wearing bikinis and bathing shorts a total of 1,525 claimed a new Russian record for the daring downhill escapade – in a temperature of around 5ºC. In fact, more have taken part in this GrelkaFest event in the past, but not during an official record attempt. (Photo by Kemerovo Online/The Siberian Times)

A Sadhu, or a Hindu holy man, performs yoga on International Yoga Day at Kamakhya temple in Guwahati, India on June 21, 2018. (Photo by Anuwar Hazarika/Reuters)

Iranian soccer fan wait for the start of the group B match between Iran and Spain at the 2018 soccer World Cup in the Kazan Arena in Kazan, Russia, Wednesday, June 20, 2018. (Photo by Diego Azubel/EPA/EFE)

Artists called “Le couple en chocolat” take part in the festival “Statues en Marche” in Marche-en-Famenne, Belgium, July 22, 2018. Living statues are a common sight in many city centres, but it is rare to see such a diverse range of this peculiar form of street art for which performers must keep still for painfully long periods of time to create the desired illusion. (Photo by Yves Herman/Reuters)

Models prepare for a presentation of the creations by Ukrainian designer Jean Gritsfeldt during Ukrainian Fashion Week at the railway station in Kiev, Ukraine on September 2, 2018. The fashion event presents 2018/19 collections by Ukrainian and international designers from 01 to 05 September 2018. (Photo by Valentyn Ogirenko/Reuters)

A contestant prepares at the backstage before the Miss Transqueen India 2018 transgender beauty pageant in Mumbai, India on October 7, 2018. (Photo by Francis Mascarenhas/Reuters)