A medical worker in protective gear sprays mist on her colleague during a hot day at an outdoor clinic for coronavirus tests at a public health facility in the southwestern city of Gwangju, South Korea, 05 June 2020. (Photo by Yonhap/EPA/EFE)

Police officers wield their batons against activists from various student unions during a protest march demanding jobs and better education facilities, in Kolkata, India, February 11, 2021. (Photo by Rupak De Chowdhuri/Reuters)

A parakeets lands on a woman's head at St James' Park in London, United Kingdom on February 9, 2021. London has been experiencing snow as the Storm Darcy hits the city. (Photo by Brett Cove/SOPA Images/Sipa USA)

A woman dressed in the style of a Hindu goddess keeps her face partially covered for a ritual during Maha Shivaratri celebrations on March 12, 2021 in Kaveripattinam, India. Maha Shivaratri is a major Hindu festival celebrated annually in honour of the god, Shiva. The festival is observed with chanting prayers, fasting, and meditating to overcome “darkness and ignorance” in life. (Photo by Abhishek Chinnappa/Getty Images)

Olga Conover of Palm Bay, Fla., walks down the bridge at sunset carrying her merged American-Ukraine flag near the end of a march marking the one-year anniversary of Russia invading Ukraine, late Thursday afternoon, February 23, 2022, in Melbourne, Fla. A small but passionate group of Ukraine supporters took the Melbourne Causeway to show their support, organized by the Ukrainian Space Coast group. (Photo by Malcolm Denemark/Florida Today via AP Photo)

A married Hindu woman performs rituals around a banyan tree at Vat Savitri festival in Ahmedabad, India, Tuesday, June 14, 2022. Vat Savitri is celebrated on a full moon day where women pray for the longevity of their husbands. (Photo by Ajit Solanki/AP Photo)

Members of kibbutz Nirim celebrate Shavuot, a Jewish holiday marking both the giving of the Torah and the wheat harvest, at the kibbutz near the border of the besieged Gaza Strip on June 1, 2025, for the first time since the October 2023 attacks by Palestinian militants. (Photo by Menahem Kahana/AFP Photo)

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)