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 Santa Claus puppet holding a Christmas tree is pictured against the sun in Berlin November 23, 2014. (Photo by Hannibal Hanschke/Reuters)

A Chinese People's Liberation Army soldier marches with members of an honor guard as they prepare for a welcome ceremony for visiting Luxembourg's Prime Minister Xavier Bettel outside the Great Hall of the People in Beijing, Monday, June 12, 2017. (Photo by Andy Wong/AP Photo)

An Indian street vendor selling bananas naps on his fruit cart at the roadside in New Delhi on June 3, 2015. (Photo by Money Sharma/AFP Photo)

In this November 30, 2017 photo, Douglas scoops up mud from the bottom of the polluted Guaire River, in search of gold and anything valuable he can sell, in Caracas, Venezuela. Some stretches of the river smell of sewer while others emit a toxic odor of fuel, a stench that stays in ones nose for hours after leaving the water. (Photo by Ariana Cubillos/AP Photo)

Chelsea Haardt #9, Melissa Margulies #2 and Ogom Chijindu #6 of the Los Angeles Temptation wait for the start of the Lingerie Football League's Lingerie Bowl IX against the Philadelphia Passion at the Orleans Arena February 5, 2012 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

Colorful hot air balloons glide across the Qicai Danxia scenic area in Zhangye City, northwest China's Gansu Province on August 17, 2023. (Photo by Rex Features/Shutterstock)

An ultra-Orthodox Jewish man holds a chicken before he performs the Kaparot ritual, where white chickens are slaughtered as a symbolic gesture of atonement, ahead of Yom Kippur, the Jewish Day of Atonement in Bnei Brak, Israel in Bnei Brak October 9, 2016. (Photo by Baz Ratner/Reuters)