The “Sarandi” stream, dyed red due to unknown contaminants allege residents, flows into the Río de la Plata on the outskirts of Buenos Aires, Argentina, February 6, 2025. (Photo by Rodrigo Abd/AP Photo)

Houseboats and charter boats are docked in the ice in the harbor at Fischerhof Eldenburg in the Mecklenburg Lake District, northern Germany, Wednesday, February 19, 2025. (Photo by Jens Büttner/dpa)

An aerial view shows a fishing boat which capsized due to weather conditions by the coast in Banda Aceh, Indonesia on June 23, 2025. (Photo by Chaideer Mahyuddin/AFP Photo)

This aerial photograph shows beach-goers gathering on a beach alongside the Atlantic Ocean in Carcans, south-western France on July 22, 2025. (Photo by Christophe Archambault/AFP Photo)

Local residents receive food from federal authorities in Xalacahuantla, Mexico, on Thursday, October 16, 2025. Hundreds of communities in central and eastern Mexico were cut off by deadly landslides and flooding caused by torrential rains. (Photo by Alfredo Estrella/AFP Photo)

Supporter Mette Peluce, 11, waits for U.S. Democratic presidential candidate Bernie Sanders to speak in East Los Angeles, California, U.S. May 23, 2016. (Photo by Lucy Nicholson/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)