A garbage collector, with his horse and cart, prepares to unload rubbish at the municipal dump in Nezahualcoyotl, on the outskirts of Mexico City, February 18, 2015. Hundreds of horse or donkey-drawn carts will disappear from the streets of a municipality in the state of Mexico, located on the outskirts of Mexico City, and will be replaced by motorized vehicles, local authorities said. (Photo by Henry Romero/Reuters)

An enterprising Chinese man pulls a bicycle cart packed high with bags of recyclable plastic containers in Shanghai July 25, 2002. The man sells each kilogram (2.2 pounds) of plastic for 0.08 yuan ($.01) to a nearby depot. (Photo by Claro Cortes IV/Reuters)

A woman, with her face covered with colored powders, dances during the Holi Festival of Colors in Lisbon, Sunday, September 15 2013. The festival, which is mainly celebrated during the Hindu spring festival Holi in some regions of India and Nepal, has become popular among people in other communities. (Photo by Francisco Seco/AP Photo)

A member of the Knights Guard cleans the ice during the Vegas Golden Knights' game against the Colorado Avalanche at T-Mobile Arena on April 28, 2021 in Las Vegas, Nevada. The Golden Knights defeated the Avalanche 5-2. (Photo by Ethan Miller/Getty Images via AFP Photo)

A veterinarian takes a sample from a cat at an animal shelter in Yeoju, southeast of Seoul, South Korea, 01 August 2023, after cats were found to have been infected with a highly pathogenic H5N1 avian influenza strain at shelters in Seoul on 25 and 29 July, marking the first infections of the virus in mammals since 2016. (Photo by Yonhap/EPA)

Palestinians, who were displaced to the south at Israel's order during the war, make their way as they return to their homes in northern Gaza, amid a ceasefire between Israel and Hamas, in Gaza City, on January 29, 2025. (Photo by Dawoud Abu Alkas/Reuters)

Luis Hernan was always curious about how wireless technologies like radio are transmitted through the air. So after finishing up his studies in architecture, computer science, and design, Hernan decided to research these invisible signals through a PhD at Newcastle University. Hernan set up a system that turned the wireless signals around him into colourful, ghostlike images using long-exposure photography, allowing people to see the strength of the signals around them. (Photo by Luis Hernan)

Contestant of the Muslimah World 2013, Obabiyi Aishah Ajibola (C) of Nigeria, is reflected in a mirror checking her make-up while contestants wait for a grand final during the Muslimah World competition in Jakarta on September 18, 2013. (Photo by Adek Berry/AFP Photo)