People protest at the Boston Free Speech Rally in Boston, USA on August 19. 2017. With the Boston Free Speech rally was closed to the media (despite the Boston Common being a public space), a lot of the media’s coverage centred on the tensions within the larger counter-protest. (Photo by Stephanie Keith/Reuters)

A citizen wearing protective suit shops at a market in Santiago, Chile, April 16, 2020 Chile has taken stringent measures to contain the virus, including imposing a night time curfew, suspending classes, closing non-essential businesses, and mandating the use of face masks on all public transit. (Photo by Jorge Villegas/Xinhua News Agency)

South Korean residents 89-year-old Jeong Nam-poong and 80-year-old Jang Yoon-hui , wearing protective masks, dance at park after their daytime discotheque “colatec” has been closed amid the coronavirus disease (COVID-19) outbreak in Seoul, South Korea, May 19, 2020. (Photo by Minwoo Park/Reuters)

A weather vane on a farm building close to the HS2 line on November 24, 2020 in Great Missenden, England. HS2 protesters continue to occupy key infrastructure sites along the proposed HS2 route claiming that the project is “the most carbon-intensive and environmentally destructive project in UK history”. (Photo by Jim Dyson/Getty Images)

Grade 5 student Lovely Joy De Castro, 11, takes notes while attending an online class using a smartphone, as schools remain closed during the Coronavirus disease (COVID-19) outbreak, at Manila South Cemetery where she lives with her family in Makati City, Philippines, November 6, 2020. (Photo by Eloisa Lopez/Reuters)

Cast member, American singer Janelle Monae attends the premiere of “Glass Onion: A Knives Out Mystery” during the closing night gala at the BFI London Film Festival in London, Britain on October 16, 2022. (Photo by Toby Melville/Reuters)

Trainees of the Tianjiao Special Guard/Security Consultant bodyguard training camp watch their instructor use a scarf to cover a student's head during a demonstration of close-quarter combat skills at a special course on flight safety inside a scale model of a passenger jet at a flight attendant training centre on the outskirts of Beijing, March 18, 2014. Inspired by the missing Malaysia Airlines Flight MH370, the company wanted to emphasize the importance of aviation safety by teaching their trainees emergency evacuation procedures and close-quarter combat skills to handle situations such as natural disasters and plane hijacks, according to the company. (Photo by Jason Lee/Reuters)

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.