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)

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)

“A Double Eagle is a gold coin of the United States with a denomination of $20. (Its gold content of 0.9675 troy oz was worth $20 at the then official price of $20.67/oz). The coins are made from a 90% gold (0.900 fine = 21.6 kt) and 10% copper alloy”. – Wikipedia

Photo: A “Double Eagle” gold twenty dollar coin is displayed above a catalogue picture showing the reverse side of the coin at Goldsmith's Hall on March 2, 2012 in London, England. Nearly half a million of these coins were originally minted in the midst of the Great Depression in the US. Only 13 are known today after the rest were melted down before they ever left the US Mint, sacrificed as part of a strategy to stabalise the American economy. In 2002 a Double Eagle sold at auction for $7.6 million. (Photo by Peter Macdiarmid/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)

“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)

Alice Ross views a gold crown which was presented to Queen Victoria, part of the Royal Collection on display at the Queens Gallery on March 13, 2012 in Edinburgh, Scotland. The exhibition, which marks Her Majesty The Queen's Diamond Jubilee, reflects the tastes of monarchs and other members of the royal family who have shaped one of the world's great art collections. (Photo by Jeff J. Mitchell/Getty Images)

A visitor looks at a Morris Mini-Minor Car on display at the Victoria and Albert museums' new major exhibition, “British Design 1948-2012: Innovation In The Modern Age” on March 28, 2012 in London, England. This car, which was designed by Alec Issigonis, was the first one off the production line. The exhibition showcases some of the most iconic product design, fashion, furniture, graphics, architecture and fine art from the last 60 years, and opens to the public from March 31, 2012. (Photo by Dan Kitwood/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)