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)

An undated archive picture shows a dog pulling a Belgian machine gun at an unknown location in northern France. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI. (Photo by Collection Odette Carrez/Reuters)

Kumari Samita Bajracharya sits in front of devotees offers during a special puja at Kumari Ghar in Patan, Nepal, 09 April 2011. It is believed that worshipping Kumari and receiving tika from her reduces illness and avoid problems. Kumari, or Kumari Devi, is a “living goddess”. The word literally means virgin in Nepali. The Living Goddesses are young pre-pubescent girls that are considered to be incarnations of the Hindu Goddess of Power, Kali. The Kumari retires when she reaches puberty. (Photo by Narendra Shrestha/EPA)

People line the streets as a dragon passes by during the Chinese New Year parade on January 29, 2012 in New York City. Thousands of people turned out to see the event which celebrated the Year of the Dragon. (Photo by John Moore/Getty Images)

People line up to buy toilet paper and baby diapers at a supermarket in downtown Caracas January 19, 2015. There's a booming new profession in Venezuela: standing in line. The job usually involves starting before dawn, enduring long hours under the Caribbean sun, dodging or bribing police, and then selling a coveted spot at the front of huge shopping lines. As Venezuela's ailing economy spawns unprecedented shortages of basic goods, panic-buying and a rush to snap up subsidized food, demand is high and the pay is reasonable. (Photo by Jorge Silva/Reuters)

In this October 16, 2014 photo, a man cleans his American classic car before going to work in Havana, Cuba. While the U.S. embargo that took effect in 1961 stopped the flow of new cars, and most parts, a few Cubans now manage to bring in replacement parts when friends or family visit from the U.S. (Photo by Franklin Reyes/AP Photo)