A large bull walrus returns to the shores of Prins Karl Forland after diving and feeding on clams. (Photo by Paul Nicklen/National Geographic). Svalbard, Norway, 2011

A model of a ghost made from translucent fibreglass is lit from inside at Gem's (Wax Models) Ltd, in the Portobello Road area of west London. The ghost is due to go to the Capistrano Mission Museum in California, where tourists are told the legend of how he frightened a young Indian girl novice to death. 1st May 1965. (Photo by Chris Ware/Keystone Features)

An enthusiast dressed as a zombie takes part in the annual Zombie Walk festival in Prague June 1, 2013. (Photo by David W. Cerny/Reuters)

This 1999 photo, supplied by HBO, shows a younger-looking James Gandolfini, who plays mob boss Tony Soprano, in an episode from the first season of the HBO cable television mob series, “The Sopranos”. Actor James Gandolfini, best known for his Emmy-winning portrayal of a conflicted New Jersey mob boss in the acclaimed HBO cable television series “The Sopranos”, has died while vacationing in Rome, the network said on June 19, 2013. (Photo by Anthony Neste/AP Photo/HBO)

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

A vehicle lies on a road in Adairsville. (Photo by David Goldman/Associated Press)

Herring worth millions in exports float dead in Kolgrafafjordur, a small fjord on the northern part of Snaefellsnes peninsula, west Iceland, for the second time in two months. Between 25,000 and 30,000 tons of fish died in December and more now, due to lack of oxygen in the fjord thought to have been caused by a landfill and bridge constructed across the fjord in December 2004. The current export value of the estimated 10,000 tons of herring amounts to $ 9.8 million, according to the newspaper “Morgunbladid”. (Photo by Brynjar Gauti/Associated Press)

Kenny Wallace, driver of the #09 Family Farmers Toyota, spins into Justin Allgaier, driver of the #31 Brandt Chevrolet, who is lifted into the air by Reed Sorenson, driver of the #52 Means Racing Chevrolet, as Michael Annett, driver of the #43 Pilot Flying J. Ford, tries to avoid the wreckage during the NASCAR Nationwide Series DRIVE4COPD 300 at Daytona International Speedway on February 25, 2012 in Daytona Beach, Florida. (Photo by John Harrelson/Getty Images for NASCAR)