The Prague astronomical clock, or Prague orloj, is a medieval astronomical clock located in Prague, the capital of the Czech Republic. The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest one still working.

A visitor walks past an installation artwork entitled “Confuciuse” which combines the word “Confucius” and “confuse” in the contemporary art exhibition at “Fun and Art” Festival on December 13, 2008 in Xian of Shaanxi Province, China. (Photo by China Photos/Getty Images)

“Jason deCaires Taylor is an English sculptor specialising in the creation of contemporary underwater sculptures which over time develop into artificial coral reefs. Taylor integrates his skills as a conservationist, underwater photographer and scuba diving instructor to produce unique installations that encourage the habitation and growth of corals and marine life”. – Wikipedia. Photo: “The Silent Evolution”. Underwater Sculpture, Museo Subacuático de Arte, Cancun. (Photo by Jason deCaires Taylor/UnderwaterSculpture)

To commemorate the centennial of Britain’s involvement in the First World War, ceramic artist Paul Cummins and stage designer Tom Piper conceived of a staggering installation of ceramic poppies planted in the famous dry moat around the Tower of London. Titled “Blood Swept Lands and Seas of Red,” the final work will consist of 888,246 red ceramic flowers—each representing a British or Colonial military fatality—that flow through grounds around the tower.

People visit Chinese artist Huang Yongping's installation art work named “Leviathanation” at Tang Contemporary Art of 798 Art District on March 29, 2011 in Beijing, China. The exhibition named “Tracing The Milky Way” will be last until May 14. (Photo by Feng Li/Getty Images)

Beekeeper and Chairman of The London Beekeepers Association John Chapple installs a new bee hive on an urban rooftop garden in Hackney on July 1, 2009 in London, England. (Photo by Dan Kitwood/Getty Images)