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 close up shows Ukraine's Hanna Ryzhykova leg breaking a hurdle before crashing out as she competes in the women's 400m hurdles heats during the European Athletics Championships at the Letzigrund stadium in Zurich on August 13, 2014. (Photo by Olivier Morin/AFP Photo)

A man dressed up as the Statue of Liberty walks in front of a new digital advertising screen in Times Square, New York, November 18, 2014. According to local media the screen is a full block long, 8 stories tall, is lit with 24 million LED pixels and has a higher resolution than most TV sets. The advertising rate is reported at $2.5 million USD for a four-week run making it one of the most expensive outdoor advertising spaces in the world. (Photo by Carlo Allegri/Reuters)

Daughter of Palestinian man Ali Daba, who decided with his wife to split their children up and mark them with bracelets to help identify them, in fear of them being killed in Israeli strikes, shows her bracelet at their shelter in Khan Younis in the southern Gaza Strip on October 24, 2023. (Photo by Ibraheem Abu Mustafa/Reuters)

National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

A university in the Philippines in March 2024 has come up with a novel way to stop students cheating in exams – by getting them to wear hats in the shape of animated characters and random objects such as a crate of beer. (Photo by Angelo Ebora/beampix/Solent news)

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)

To most of us, hand-feeding crocodiles might sound like a one-way ticket to a watery grave. But for Jose Eduardo Chaves Salas, 32, coming within inches of the fearsome creatures’ razor-sharp teeth is all in a day’s work. He runs Jose's Crocodile River Tour on the Tarcoles River in Costa Rica, where tourists can watch him feed crocs up to 17 feet long. Photo: A tour guide shows a thumbs up as he sits on top of a crocodile on the Tarcoles river in Tarcoles, Costa Rica. (Photo and caption by Barcroft Media)