Protesters wear masks, the left in the colors of the Kenyan national flag, as they join others carrying mock coffins and red-painted crosses, symbolizing the blood of the 28 non-Muslims singled out and killed in the recent attack on a bus in Mandera by Somali militant group al-Shabab, outside government offices in downtown Nairobi, Kenya Tuesday, November 25, 2014. (Photo by Ben Curtis/AP Photo)

In this third of seven sequential photos, Elian Gonzalez is held in a closet by Donato Dalrymple, one of the two men who rescued the boy from the ocean, right, as government officials search the home of Lazaro Gonzalez for the young boy, early morning, April 22, 2000, in Miami, Florida. Armed federal agents seized Elian Gonzalez from the home of his Miami relatives before dawn, firing tear gas into an angry crowd as they left the scene with the weeping 6-year-old boy. This photo won the Prize in 2001. (Photo by Alan Diaz/AP Photo)

The “Assignments” exhibition is an annual chance to see the top images by UK photojournalists, as chosen by the British Press Photographers’ Association. Here: Wales’s Cory McKenna dominates Micol DiSegni during their fight at Cage Warriors 97 in Cardiff, 29 September 2018. (Photo by Chris Fairweather/Huw Evans Agency)

This combination of April 15, 2013 and April 2, 2014 photos show a police officer clearing Boylston Street following a bomb blast near the finish line of the 2013 Boston Marathon, and pedestrians crossing at the same corner nearly a year later in Boston. (Photo by Charles Krupa/AP Photo)

Visitors attend a press preview of the 2012 Whitney Biennial at the Whitney Museum of American Art on February 27, 2012 in New York City. The contemporary art exhibition includes sculpture, photography, painting, installations, dance, theater, film and music and runs from March 1 through May 27. (Photo by Mario Tama/Getty Images)

An employee looks at the artwork “4-Chlorephenol, 2008”, part of the artist Damien Hirst's exhibition “The Complete Spot Paintings” at the Gagosian Gallery on January 12, 2012 in London, England. (Photo by Matthew Lloyd/Getty Images)

A general view of the Coe Collection of American Indian Art press view at the Metropolitan Museum of Art on December 19, 2011 in New York City. (Photo by Dario Cantatore/Getty Images)

“Today, we take photography for granted. Anyone can take a photograph simply by pressing a button. Yet, it was not always so simple. The invention of photography was announced in 1839, but during its first fifty years taking a photograph was a complicated and expensive business. In 1888, all this was to change following the appearance of a camera that was to revolutionize photography. Popular photography can properly be said to have started 120 years ago with the introduction of the Kodak”. – The UK National Media Museum. Photo: Two men on the deck of a ship, about 1890. (Photo by Collection of National Media Museum/Kodak Museum)