A section of multi-vehicle accident on Interstate 75 is shown in Detroit, Thursday, January 31, 2013. Snow squalls and slippery roads led to a series of accidents that left at least three people dead and 20 injured on a mile-long stretch of southbound I-75. More than two dozen vehicles, including tractor-trailers, were involved in the pileups. (Photo by Paul Sancya/AP Photo)

A dead body is seen on the ground after violence erupted in the Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by David Mdzinarishvili/Reuters)

Bristol Zoo's baby gorilla Kukena holds onto his mother's arm as he ventures out of his enclosure at Bristol Zoo's Gorilla Island on May 4, 2012 in Bristol, England. The seven-month-old western lowland gorilla is starting to find his feet as he learns to walk having been born at the zoo in September. Kukena joins a family of gorillas at the zoo that are part of an international conservation breeding programme for the western lowland gorilla, which is a critically endangered species. (Photo by Matt Cardy)

Visitors of the world's longest tree top walk between the trees of the Bavarian forest on November 6, 2009 in Neuschoenau, Germany. The path, 1300 meters long and in 8 to 25m height, winds up to an impressive tower with a height of 44 meters. The wooden construction is integrated into the forest and delivers a natural experience. (Photo by Miguel Villagran/Getty Images)

A Dartmoor Hill pony foal runs on the moor on Dartmoor on May 17, 2011 in Princetown England. Although a tourist attraction, especially during the foaling season and often seen as part of the landscape of Dartmoor, many ponies face an uncertain future due to unsustainable breeding and their falling market values. The charity South West Equine Protection estimates that last year 1500 ponies were slaughtered – with many being sold for lion meat to nearby zoos. Along with other equine charities, they are calling for the removal of stallions from the moor to bring numbers down to sustainable levels. (Photo by Matt Cardy/Getty Images)

A humpback whale is seen at the beginning of whale watching season during a Manly Whale Watching tour on June 8, 2011 in Sydney, Australia. The first day of winter in New South Wales, June 1st, marks the start of the Humback and southern right whales migration from southern regions to the north to warmer waters. Whale watchers should expect tohave plenty to see with the whale population increasing each year. The migration north continues through July and with the whales returning between September and November. (Photo by Cameron Spencer/Getty Images)

A wounded protester is attended before being rushed to a vehicle following violence in Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by Konstantin Chernichkin/Reuters)