Coaches of the North-East Express passenger train that derailed late Wednesday near Raghunathpur railroad station in Buxar district of Bihar state, India, Thursday, October 12, 2023. The train was on its way to Assam state from New Delhi. (Photo by Aftab Alam Siddiqui/AP Photo)

Flower garlands, fruits and a pair of sandals of a woman who died from the coronavirus disease (COVID-19), are placed by her relatives on the spot where she was cremated, as part of a ritual at a crematorium in New Delhi, India, April 30, 2021. (Photo by Adnan Abidi/Reuters)

A woman poses for photos in snowfall on a podium installed on International Women's Day in central St. Petersburg, Russia, Wednesday, March 8, 2023, with a police officer in the background. International Women's Day on March 8 is an official holiday in Russia, where men give flowers and gifts to female relatives, friends and colleagues. (Photo by Dmitri Lovetsky/AP Photo)

A honour guard soldier gives a flower to a girl on International Women's Day in St. Petersburg, Russia, Friday, March 8, 2024. International Women's Day on March 8 is an official holiday in Russia. Per tradition, men give flowers and gifts to female relatives, friends and colleagues, even though in the past two years flowers have gotten more expensive. Marches, demonstrations and conferences are being held the world over, from Asia to Latin America and elsewhere. (Photo by Dmitri Lovetsky/AP Photo)

The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

Women perform square dancing at a park square in Beijing, China, April 9, 2015. Chinese-style square dancing is running circles around other hobbies for the elderly, with millions taking to parks and plazas across China, swivelling their hips and rolling their arms – but it's not to everyone's liking. (Photo by Kim Kyung-Hoon/Reuters)

A Tibetan man stirs butter tea made for the arriving guest during the function organised to mark Losar or the Tibetan New Year at a Tibetan Refugee Camp in Lalitpur February 19, 2015. Tibetans across the world marked the arrival of the New Year with prayers and festivities. (Photo by Niranjan Shrestha/AP Photo)

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)