Eurocopter's X³ high-speed hybrid helicopter demonstrator performs, September 6, 2010. The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Eurocopter (now Airbus Helicopters). A technology demonstration platform for Eurocopter “high-speed, long-range hybrid helicopter” or H³ concept, the X³ achieved 255 knots in level flight on 7 June 2013, setting an unofficial speed record for a helicopter. (Photo by Reuters/HO/Eurocopter/Penna)

Indian bride takes part in a mass marriage ceremony under chief minister's welfare scheme (Mukhyamantri Kanyadan Yojna) on the occasion of the Basant Panchami festival, in Bhopal, India, 30 January 2020. (Photo by Sanjeev Gupta/EPA/EFE/Rex Features/Shutterstock)

A commuter gestures to Boris Johnson as he rides across Vauxhall Bridge in London, England on November 19, 2015. The London mayor was opening a cycle superhighway. (Photo by John Stillwell/PA Wire)

Tens of millions of red crabs make their way across Christmas Island, Australia on November 13, 2021 during their annual migration from the forest to the ocean, swamping roads and bridges. (Photo by Parks Australia/Animal News Agency)

MY Raven, a former steamer now converted to diesel, cruises across Ullswater from Glenridding to Pooley Bridge in Cumbria, UK on October 25, 2024. (Photo by Andrew McCaren/London News Pictures)

Penitentes, or nieves penitentes (Spanish for “penitent-shaped snows”), are a snow formation found at high altitudes. They take the form of tall thin blades of hardened snow or ice, closely spaced with the blades oriented towards the general direction of the sun.

A staff member (R) looks on next to a cake, which was baked in the shape of a muscular man, for customers to try for free during a promotional event of a cake store in Shenyang, Liaoning province, China, December 6, 2015. (Photo by Reuters/Stringer)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)