“Daredevil Nik Wallenda became the first person to walk on a tightrope across the Niagara Falls, taking steady, measured steps June 15, 2012 for 1,800 feet across the mist-fogged brink of the roaring falls separating the U.S. and Canada”. (Photo by John Moore/David Duprey/AP Photo)

People pray inside a temple at the Janmashtami Hindu Festival at Bhaktivedanta Manor on August 22, 2011 in Watford, England. Up to 72,000 were expected to take part in the two day festival celebrating the birth of Krishna, in what is believed to be the largest Hindu festival gathering outside of India. (Photo by Dan Kitwood/Getty Images)

A Wiesel combat vehicle of the German Bundeswehr armed forces takes part in a demonstration for visitors prior to military exercises on September 28, 2011 near Munster, Germany. The Bundeswehr has instituted far-reaching changes in recent years, including an end to compulsory military service. (Photo by Sean Gallup/Getty Images)

Revelers dressed as Santa Claus drink outside at a bar during the annual SantaCon event December 10, 2011 in New York City. SantaCon is a mass gathering of revelers dressed as Santa Claus who take to the streets in cities across the country before Christmas. (Photo by Allison Joyce/Getty Images)

Israelis of Ethiopian origin take part in a rally against racism on January 10, 2012, in the southern Israeli town of Kiryat Malachi, Israel. Hundreds of demonstrators hit the streets of Kiryat Malachi, protesting what they call the discrimination of Ethiopian immigrants. According to Ethiopian residents of Kiryat Malachi, housing committees in the city have been refusing to sell them apartments. (Photo by Uriel Sinai/Getty Images)

Artist Vik Muniz is known for his gigantic composite installations and sculptures created from thousands of individual objects. In this new collaboration with artist and MIT researcher Marcelo Coelho, Muniz takes the opposite approach and explores the microscopic with a new series of sandcastles etched onto individual grains of sand.

The Sydney Skyline is seen before the lights are switched off for Earth Hour on March 26, 2011 in Sydney, Australia. Earth Hour encourages individuals around the world to turn off their lights for one hour at 20:30 local time on March 26, 2011 to take a stand against climate change. The largest Earth Hour was in 2010 when 128 countries participated.

Three one-month-old lioness cubs are held by a keeper as they take their first outing on February 21, 2010 at the Ramat Gan Safari Park near Tel Aviv, Israel. The still unnamed cubs are the first triplet females to be born at the safari park and officials say their birth will ensure the continuity of the park's pride of lions. (Photo by David Silverman/Getty Images)