Opossums on their mothers back at a game reserve in Central Minnesota, USA, on September 2, 2013. (Photo by Caters News Agency)

The Chavo del Ocho balloon makes its way along the streets during an annual Christmas parade at Santiago town in Chile, December 13, 2015. (Photo by Pablo Sanhueza/Reuters)

New York Islanders' Matt Martin (17) and Pittsburgh Penguins' Zach Aston-Reese (12) fight during the second period in Game 2 of an NHL hockey Stanley Cup first-round playoff series in Pittsburgh, Tuesday, May 18, 2021. Both players received a two-minute minor penalty. (Photo by Gene J. Puskar/AP Photo)

A woman holds an elderly woman on her back to cross a flooded street after a heavy rain in Shenyang, Liaoning province on July 14, 2017. (Photo by Fred Dufour/AFP Photo)

President Barack Obama with does the tango with a dancer during the State Dinner at the Centro Cultural Kirchner, Wednesday, March 23, 2016, in Buenos Aires, Argentina. (Photo by Pablo Martinez Monsivais/AP Photo)

Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

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 twelve foot long giant hamster has surprised Londoners along the South Bank, Millennium Bridge and Clapham Common on May 26, 2016. A 4-metre pedal-powered mechanical model hamster, which has been created in the likeness of Jaffa the hamster, who is listed as one of the 10 oddest discoveries made by Kwik Fit technicians in customers’ cars. (Photo by Joe Pepler/Rex Features/Shutterstock)