Mount Etna erupts

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, December 7, 2015. REUTERS/Antonio Parrinello

A photographer takes pictures of Italy's Mount Etna spewing lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello

People watch Italy's Mount Etna spewing lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello

Italy's Mount Etna as it erupts on the southern island of Sicily, November 17, 2013.REUTERS/Antonio Parrinello

A photographer takes pictures of Italy's Mount Etna spewing lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello

Italy's Mount Etna spews lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello

Italy's Mount Etna spews lava as it erupts on the southern island of Sicily, November 16, 2013. REUTERS/Antonio Parrinello

Italy's Mount Etna spews lava as it erupts on the southern island of Sicily, November 17, 2013. REUTERS/Antonio Parrinello