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)

Turkey's Merve Aydin cries after she came in last in her women's 800m round 1 heat at the London 2012 Olympic Games at the Olympic Stadium August 8, 2012. (Photo by Lucy Nicholson/Reuters)

The giant inflatable Rubber Duck installation by Dutch artist Florentijn Hofman floats on the Parramatta River, as part of the 2014 Sydney Festival, in Western Sydney, January 10, 2014. The creation is five stories tall and five stories wide and has been seen floating in various cities around the world since 2007. (Photo by Jason Reed/Reuters)

Russian honour guards wearing protective masks attend the opening ceremony of the 6th International Military Technical Forum “Army 2020” and Army Games in the military Patriot Park outside Moscow on August 23, 2020. (Photo by Kirill Kudryavtsev/AFP Photo)

Murad Khydyrov, horse and monkey trainer at the Great Moscow State Circus, and chimpanzee named Micky get ready for a rehearsal of the show called “History” as the circus prepares for its new season, which is to begin on September 19, in Moscow on September 17, 2020. (Photo by Natalia Kolesnikova/AFP Photo)

Members of the LSU Golden Girls dance team sit spaced apart wearing masks, under COVID-19 restrictions, requiring social distancing and masks, before an NCAA college football game between the LSU and the Mississippi State in Baton Rouge, La., Saturday, September 26, 2020. (Photo by Gerald Herbert/AP Photo)

An Armenian serviceman fires a cannon towards Azerbaijan positions in the self-proclaimed Republic of Nagorno-Karabakh, Azerbaijan, Tuesday, September 29, 2020. (Photo by Sipan Gyulumyan/Armenian Defense Ministry Press Service/PAN Photo via AP Photo)