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)

A military cadet gets help from a colleague to adjust her hair before taking part the military parade in Bucharest, Romania, Saturday, December 1, 2018, as thousands turned out Saturday to celebrate 100-years since Romania became a modern-day state, amid concerns about rule of law and the state of democracy. Crowds braved temperatures of minus 5 Celsius (23 Fahrenheit) to watch the military parade of troops, tanks and military vehicles. (Photo by Vadim Ghirda/AP Photo)

Two friends attempt to balance in the icy conditions in Newcastle, England on February 2, 2019. Boozy Brits across the UK took to the streets last night to ensure they got February off to a wet start after “Dry January”. (Photo by Craig Connor/North News and Pictures)

Winner Petra Vlhova from Slovakia celebrates on the podium of the FIS women's World Cup slalom in Zagreb, the “Snow Queen Trophy 2022”, on January 4, 2022. (Photo by Antonio Bronic/Reuters)

France's Alexia Richard looks up after falling in. loss to Spain in a beach volleyball match at the 2024 Summer Olympics, Wednesday, July 31, 2024, in Paris, France. (Photo by Robert F. Bukaty/AP Photo)

Ducati Lenovo's Italian rider Francesco Bagnaia rides during the free practice 1 session of the MotoGP Thailand Grand Prix at the Buriram International Circuit in Buriram on February 28, 2025. (Photo by Mohd Rasfan/AFP Photo)

A person lights fire crackers during the celebrations of Mawlid al-Nabi, the birth anniversary of Prophet Muhammad, in Hyderabad, Pakistan, 04 September 2025. Mawlid is observed on the 12th day of Rabi al-Awwal (the third month of the Islamic calendar) in Sunni Islam and on the 17th day in Shiite Islam. (Photo by Nadeem Khawar/EPA)

Robert Price of TREWGrip LLC demonstrates a TREWGrip handheld rear-type keyboard and air mouse for Apple and Android tablets at the “CES: Unveiled”, media preview for International CES, at the Mandalay Bay Convention Center in Las Vegas on January 5, 2014. (Photo by Robyn Beck/AFP Photo)