Plaster cast moulds of victims of the Mount Vesuvius eruption lie on a display table in a laboratory at Pompeii October 13, 2015. An expert team made up of archaeologists, radiologists, orthodontists and anthropologists began on September 2015 to use CAT scan technology (computerised axial tomography) to peer inside the plaster cast moulds of Pompeii's victims, in a study that has added more detail to previous findings. A 16-layer scan had to be used in order to penetrate the hardened plaster but the results showed up impressive skeletal remains and near perfect teeth. (Photo by Alessandro Bianchi/Reuters)

After some days with temperatures below freezing point, I was out skating at some lakes at the outskirts of Oslo in Norway. After a while I noticed something on the ice. To my astonishment it was a dead frozen frog.

A boy does a bicycle kick as he practises on the Marina beach ahead of the World Cup soccer tournament in Brazil, in Chennai June 4, 2014. REUTERS/Babu

Yakutsk, with a population of around 270,000, holds its own title: that of the coldest city on Earth. Here: Frost-encrusted house in the city centre. (Photo by Amos Chapple/Courtesy Images/RFE/RL)

A partially frozen Niagara Falls is seen on the American side lit by lights during sub freezing temperatures in Niagara Falls, Ontario March 3, 2014. (Photo by Mark Blinch/Reuters)

The twin lighthouses of St Joseph on Lake Michigan have been transformed by a winter storm. Ice encases the buildings, giant icicles hang from the piers and the beach is frosted white. Here: Huge icicles hang from the pier. (Photo by Mike Kline/Barcroft Media)

A 20-year-old Japanese macaque monkey named Monday scratches her eyes while suffering an allergy to pollen from the cedar tree at Awajishima Monkey Centre on March 17, 2013 in Sumoto, Japan. Many monkeys are suffering the effects of hay fever at this time of the year, with the typical symptoms being the same as with humans. According to Awajishima Monkey center this year hay fever is higher than last year, the pollen season is from February to April. (Photo by Buddhika Weerasinghe)