In this photo taken on Saturday, November 16, 2013, Mt. Etna, Europe's most active volcano, spews lava during an eruption as seen from Acireale, near the Sicilian town of Catania, Italy. (Photo by Carmelo Imbesi/AP Photo)

Summit, an Australian shepherd, makes a leaping catch of a frisbee at the pet trade fair (Heimtiermesse) at Velodrom on November 2, 2012 in Berlin, Germany. Exhibitors are showing the latest trends in collars, snacks and other accessories for cats, dogs and other household pets. (Photo by Sean Gallup)

Fighters from Germany take up position before competing in the Medieval Combat World Championship at Malbork Castle, northern Poland, April 30, 2015. Medieval combat is a full contact sport that revives the foot based tournament fighting of medieval Europe. Countries fight in refereed matches where the objective is to get the opposing team to the floor. There are also duels with polearms, swords and shields where the number of hits landed are scored. The fighters, both male and female, wear heavy armours and weapons, mostly replicas of authentic pieces, and fight following the knights code of conduct. According to organizers, 25 nations from 6 continents are taking part in the Championships, which started on April 30 and will go on until May 3. (Photo by Kacper Pempel/Reuters)

A villager run as Mount Sinabung erupt at Sigarang-Garang village in Karo district, Indonesia's North Sumatra province, February 1, 2014. Four people died and more than 28, 000 villagers have been evacuated since authorities raised the alert status for the volcano to the highest level in November 2013, local media reported on Saturday. (Photo by Reuters/Stringer)

This is the mesmerising image of a colourful Milky Way shining down on Mount Fuji. Steve Lance Lee, 37, captured the sky above the iconic mountain whilst on his honey moon in Lake Kawaguchiko, Japan. Mount Fuji is illuminated underneath the galaxy of stars, creating an impressive landscape. Here: The beautiful image captured by Steve Lance Lee of the Milky Way seemingly errupting from Mt. Fuji in Japan. (Photo by Steve Lance Lee/Caters News)

A purebred Spanish horse is pictured during the Sicab International Pre Horse Fair which is dedicated in full and exclusively to the purebred Spanish horse in the Andalusian capital of Seville, southern Spain November 17, 2015. (Photo by Marcelo del Pozo/Reuters)

Paintings are moved on a stand at the “London Art Fair” on January 18, 2012 in London, England. The fair includes over 100 different stands featuring work by well known 20th century British artists and showcases some of the best emerging talent in the art world today. The show runs until January 23, at Business Design Centre in Islington. (Photo by Dan Kitwood/Getty Images)

A woman uses the Aurasma app on an iPad which displays a virtual 3D animation of a Thundercat character which her colleague pretends to fight at the 2012 London Toy Fair at Olympia Exhibition Centre on January 24, 2012 in London, England. The annual fair, which is organised by the British Toy and Hobby Association, brings together toy manufacturers with retailers from around the world. (Photo by Oli Scarff/Getty Images)