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)

The Rio de Janeiro Olympics kick off on August 5 for some two weeks of competitive games drawing athletes as well as audiences from around the world. As they prepare to cover the event, Reuters photographers look back on their favourite pictures from past Olympics where they captured the action on the ground as well as the participants' tears and joy that followed. (Photo by Lucy Nicholson/Reuters)

Dr. Hannah Cobb from The University of Manchester looks at a viking sword during a viewing at CFA Archaeology of artefacts discovered from the first fully intact Viking boat burial site on October 18, 2011 in Edinburgh, Scotland. (Photo by Jeff J Mitchell/Getty Images)

A picture of Moon Ji-sung, a high school student who died in the Sewol ferry disaster, hangs in her room in Ansan April 7, 2015. Her dream was to be a flight attendant. Nearly a year after the Sewol ferry sank on April 16, 2014, with the death of 250 students, some families keep their children’s bedrooms intact to remember and honour their loved ones. More than 300 people, most of them students and teachers from Danwon High School, are dead, or missing and presumed dead, after the Sewol ferry sank on a routine trip from the port of Incheon, near Seoul, to the holiday island of Jeju. (Photo by Kim Hong-Ji/Reuters)

A man poses in front of a portrait of late Chinese Chairman Mao Zedong during the opening of an exhibition of Mao related art in Beijing, China, September 8, 2016. (Photo by Thomas Peter/Reuters)

Natalia Grossman of the USA competes during the women's finals of the IFSC Climbing World Cup Meiringen on April 09, 2022 in Meiringen, Switzerland. (Photo by Marco Kost/Getty Images)

A handout photo made available by Borneo Orangutan Survival Foundation (BOSF) shows veterinarian wearing protective masks and suit, conducting anesthesia procedure on Nenuah, a nine year old Bornean Orangutan before being transported and released to the Bukit Batikap protection forest, at the Nyaru Menteng Orangutan Rehabilitation Center in Palangkaraya, Central Kalimantan, Indonesia, 15 February 2021. BOSF and the national nature conservation agency (BKSDA) released 10 orangutans back to the wild in Bukit Batikap Protection Forest in Central Kalimantan and the Kehje Sewen Forest in East Kalimantan amid the pandemic according to BOSF. (Photo by BOSF Handout/EPA/EFE)

Rocky the cat's recovery from a nerve condition in his legs is coming along swimmingly – thanks to regular hydrotherapy sessions at a 20ft-long swimming pool in United Kingdom in the second decade of March 2022. The two-year-old wears a life vest to help keep him afloat and needs a plastic toy to lure him from one end of the pool to the other. (Photo by Max Willcock/BNPS Press Agency)