Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Macro or Micro? Scientists’ pictures baffle our sense of scale. It began when Stephen Young, a geography professor at Salem State University in Massachusetts, tricked his biologist colleague Paul Kelly into thinking a satellite image was one of his electron microscope scans. Can you guess whether they are close-up or very far away? (Photo by Paul Kelly)

European Space Agency astronaut Tim Peake will return home after a six-month long mission on the International Space Station,on June 18, 2016. Peake was the first British ESA astronaut to visit the ISS and captured hundreds of photographs of the Earth during his mission. Here: “Lots of sun-glint right now during our whole orbit – we haven't seen a sunset for over 3 days”, he wrote. (Photo by Tim Peake/ESA/NASA)

A mouse rides on the back of a frog in floodwaters in the northern Indian city Lucknow June 30, 2006. (Photo by Pawan Kumar/Reuters)

Vogue Italia is hosting a series of shows in Milan exploring how the magazine seeks to engage with hot social and political issues and provoke debate through images by top photographers. The Photo Vogue festival in Milan is hosting three exhibitions. The first, Fashion and Politics in Vogue Italia, looks at the magazine’s ambition to be a catalyst for change – in subtle and playful ways. Here: David LaChapelle – October 2004. (Photo by David LaChapelle/The Guardian)

Jorge Diaz punches Teon Kennedy during their USBA Super Bantamweight bout during Top Rank's 'Featherweight Fury' on March 26, 2011 at Boardwalk Hall in Atlantic City, New Jersey.

“HA Schult, born Hans-Jürgen Schult on June 24, 1939 in Parchim, Mecklenburg is a German installation, happening and conceptual artist known primarily for his object and performance art and more specifically his work with garbage”. – Wikipedia

Photo: German artist Ha Schult stands with his “trash people” below the pyramids May 15, 2002 in Giza, Egypt. Inspired by the statues of the terracotta army of Chinese Emperor Quin Shi Huangdi (247–206 B.C.), the thousand piece sulpture has stood in Red Square in Moscow, La Defense in Paris and the Great Wall in China. Schult, born in 1939 wants to bring the “trash war” to the world's attention beause trash is the greatest battle facing mankind. (Photo by Norbert Schiller/Getty Images)