Smoke plumes rise from Mount Etna, one of the most active volcanoes in the world in Sicily, Italy on June 28, 2016. (Photo by Etna Walk/Rex Feature/Shutterstock)

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, Italy, February 28, 2017. (Photo by Antonio Parrinello/Reuters)

Hot lava trickles down from the Stromboli volcano on August 9, 2014 in Aeolian Islands, Italy. Lava flows down the Mount Stromboli off the Sicilian coast in southern Italy. The volcano – at 3,034ft – is one of the most active in Europe and has been erupting continuously since 1932. (Photo by Tom Pfeiffer/Barcroft Media)

A Aldabra Tortoise receives a Christmas treat at Taronga Zoo on December 14, 2012 in Sydney, Australia. Taronga Zoo celebrated Christmas early giving Christmas-themed environmental activities to the Zoo's Giraffes, Sun Bears, Meerkats, Aldabra Tortoise and Cockatoos providing a wonderful natural display for Zoo visitors. (Photo by Lisa Maree Williams)

An elderly man uses a fan to shade himself from the sun as he walks in a public park in Beijing, Tuesday, June 7, 2016. Thursday marks the Duanwu Festival, a public holiday in China celebrated with outdoor activities including dragon boat races. (Photo by Mark Schiefelbein/AP Photo)

One of only three active female blimp pilots in the world, Kristen Arambula guides her passengers towards the Goodyear blimp “Spirit of America” in Carson, California August 5, 2015. Christened in 2002, the air ship is being retired after 8,000 flights and replaced with a newer more modern version named the “Spirit of Innovation” in September. (Photo by Mike Blake/Reuters)

Indonesian tourists take a selfie as Mount Bromo spews volcanic material and ash into the air during an eruption in Probolinggo, East Java, Indonesia, 31 December 2015. Indonesia's Mount Bromo is on the second highest alert level as its activity has increased in the last two months. (Photo by Fully Handoko/EPA)