Dancers pose for a photo as they prepare during Festival Cilung or “Love the Environment” Festival, where boats made from recycled materials, mostly plastic bottles, sail on the Ciliwung River, one of the most polluted rivers in the world, to raise public awareness about river pollution, in Jakarta, Indonesia, on September 28, 2025. (Photo by Willy Kurniawan/Reuters)

Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization. The name translates approximately as “roughened or agitated waves”.

Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)

Revellers help a man crowdsurf as they watch The Slaves perform on The Other Stage at the Glastonbury Festival of Music and Performing Arts on Worthy Farm near the village of Pilton in Somerset, South West England, on June 30, 2019. (Photo by Oli Scarff/AFP Photo)

Ballerinas perform during an ice-cream factory promotional event at an observation floor of the Moscow International Business Centre, also known as “Moskva-City”, in Moscow, Russia October 25, 2018. (Photo by Shamil Zhumatov/Reuters)

Milena Jami whips her llama to win the first place in the a race for children of ages seven and eight at the Llanganates National Park, Ecuador, Saturday, February 8, 2020. Wooly llamas, an animal emblematic of the Andean mountains in South America, become the star for a day each year when Ecuadoreans dress up their prized animals for children to ride them in 500-meter races. (Photo by Dolores Ochoa/AP Photo)

A person dressed as the mascot of Tokyo Tower wears a face shield while waiting to greet patrons at the entrance of the 332.9m (1,092ft.) high tower on May 28, 2020, as the city's landmark reopened following the lifting on May 25 of the state of emergency, imposed due to the COVID-19 novel coronavirus outbreak. (Photo by Philip Fong/AFP Photo)

Filipino children play at a fishing village along the coast of Manila Bay, Philippines, 30 May 2023. As a precaution of approaching Typhoon Mawar, Philippine government authorities have evacuated thousands of residents, imposed a no-sail ban, suspended school classes, and shutdown offices in the northern part of Luzon island, the country's largest and most populous island. (Photo by Francis R. Malasig/EPA/EFE/Rex Features/Shutterstock)