These photographs appear to show a spectacular underwater world making it ideal for scuba divers – in central Europe. Twelve metres of water covers trees, footpaths, benches and bridges that are usually accessible throughout the year. Visitors to the Green Lake in Tragoess, Austria, that is normally only one metre deep, can leisurely stroll around the picturesque lagoon. Photo: A diver crossing a bridge in the flood water. (Photo by Solnet/The Grosby Group)

“The Family of Man” opened at The Museum of Modern Art in January 1955 and was curated by Edward Steichen. It was groundbreaking in its scope – 503 images by 273 photographers from 68 countries – as well as in the numbers of people who experienced it on its tour through 88 venues in 37 countries. The touring exhibit drew over 9 million people and the accompanying catalog sold over 2.5 million copies. Here: “Coney Island, New York”, by American photographer Garry Winogrand, circa 1952. (Photo by Garry Winogrand)

“A robot suit that can help the elderly or disabled get around was given its global safety certificate in Japan on February 27, 2013, paving the way for its worldwide roll-out”. Photo: Robot suit “Hybrid Assistive Limb (HAL)” worn by a man developed by University of Tsukuba is seen lifting a 30kg weight during 2005 International Robot Exhibition on November 30, 2005 in Tokyo, Japan. By wearing the power suit, it makes it easier to move and lift heavy things. (Photo by Koichi Kamoshida)

Demonstrators wear skull masks during an anti government protest, as Chile's President Michelle Bachelet delivers a speech inside the National Congress, in Valparaiso city, Chile May 21, 2016. (Photo by Ivan Alvarado/Reuters)

U.S. Corporal Stanley Suski, left, and Miss Tamako, a Geisha girl, whirl a bit of Jitterbug, in a bar, in Tokyo, Japan, on October 1, 1945. (Photo by AP Photo)

A little boy shouts “Earthquake!” during a shouting contest, part of the annual evacuation drill on the National Disaster Prevention Day on September 1, 1986. The contest was aimed at teaching youngsters the importance of telling neighbors quickly and loudly of a disaster when it hits. The drill is annually conducted through out the country on the day marking the anniversary of the Great Kanto Earthquake that hit the Japanese capital and its vicinity on September 1, 1923, killing more than 104,000 people. (Photo by Sadayuki Mikami/AP Photo)

With more than 40,000 followers on Twitter and 26,400 fans on Vine, it looks like Marutaro the hedgehog from Japan is one of the most popular hedgehogs on the Internet. And as his owner keeps on posting Marutaro’s pictures online daily, Marutaro’s popularity continues to grow. There are hundreds of cute photographs and videos of this little fellow, but the ones with little paper cut-out faces are probably the cutest. As Marutaro lies on his back, his owner gives him a variety of silly expressions and smiles. The 20 best of them will definitely boost your mood!