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)

Three Palestinian women sit on a beachfront as a wave comes rushing by in Gaza City on November 17, 2016. (Photo by Mohammed Abed/AFP Photo)

A British policewoman chasing after a group of naked street boys by the Serpentine in Hyde Park, London. (Photo by Reg Speller/Getty Images). 1926

Pakistani students look out from a vehicle on their way to school near the Army Public School which was targeted by Taliban militants last year, in Peshawar, Pakistan, Monday, January 12, 2015. (Photo by B.K. Bangash/AP Photo)

A woman walks at the Boulevard of the River the eve of the International Women's Day, in Cali, Colombia, 07 March 2019. (Photo by Ernesto Guzman Jr./EPA/EFE)

The Niterói Contemporary Art Museum (Museu de Arte Contemporânea de Niterói — MAC) is situated in the city of Niterói, Rio de Janeiro, Brazil, and is one of the city’s main landmarks. It was completed in 1996.