These incredible pictures show Europe's largest active volcano putting on a rare and spectacular 'smoke ring' display.

Holidaymakers caught the moment Mount Etna in Sicily, Italy blew rare volcanic vortex rings into the sky.

The phenomenon happens when rings made of vapour are generated by the release of rapid gas and comes after the opening of a new circular crater.

The circular rings can be seen in the sky above the tourists and volcano at 1pm in the afternoon.

Juliet and Richard, from London, were holidaying in Sicily with their two young sons when they witnessed the rings on April 5.

Juliet said: "It was amazing and out of this world.

"Our coach driver who took us up the mountain was so excited as he hadn’t seen rings like that for ten years - he said he was going to call it 'Ring Day'.

"We knew we were witnessing something special."

The volcano Mount Etna sits above the town of Bronte, on Sicily at 11,014 feet and activity had been recorded there for more than 3,500 years.