A stray dog tries to catch birds on a frozen lake in a park in Bucharest on January 30, 2012. Temperatures plunged to -27 C in central Romania, where at least four people have died due to the cold.
- [DANIEL MIHAILESCU/AFP/Getty Images]

Sea waters have frozen over in Constanta, 230km east of Bucharest. Temperatures as low as -34 C have been reported in central Romania.
- [DANIEL MIHAILESCU/AFP/Getty Images]

People walk on a solid dam next to the frozen Black Sea in Romania.
- [DANIEL MIHAILESCU/AFP/Getty Images]

A woman looks through an icy window on a tram in Sofia on January 31, 2012. Record low temperatures were registered around Bulgaria on Tuesday, threatening shipping on the Danube and closing hundreds of schools.
- [DIMITAR DILKOFF/AFP/Getty Images]

Not everyone has been put off by the cold. Here a man bathes in the icy waters of a pond at the Victory Park in St. Petersburg, where the air temperature was -15 C.
- [OLGA MALTSEVA/AFP/Getty Images]

A man rides a horse through snow in the village of Vrapce in southern Serbia, on February 1, 2012. The Serbian army has been deployed to take supplies to remote villages trapped in heavy snowfall.
- [SASA DJORDJEVIC/AFP/Getty Images]

A girl wraps up warm in the center of Kiev on February 1, 2012. At least 43 have died of hypothermia in the Ukraine over the past six days, most of them homeless. More than 800 people have sought medical help for frostbite and hypothermia.
- [SERGEI SUPINSKY/AFP/Getty Images]

Homeless Poles have been taking shelter in Warsaw's underground heating ducts. Freezing temperatures have killed nine more people in Poland in the last 24 hours, bringing the overall toll to 29 since the cold snap began a week ago.
- [JANEK SKARZYNSKI/AFP/Getty Images]

People walk on the Karakoy landing and Galata bridge in Istanbul on January 31 after a snowfall. Heavy snow blanketed Turkey's commercial hub, paralysing daily life and disrupting air, land and sea transport.
- [BULENT KILIC/AFP/Getty Images]

A man shovels snow in the town of Veria, some 510km north of Athens. Dozens of villages around Greece have been cut off due to heavy snowfall and more low temperatures are expected next week.
- [SAKIS MITROLIDIS/AFP/Getty Images]

Children play inside the snow-covered Castello Sforzesco in Milan. Forecasters say this week will be the coldest Italy has known in 27 years.
- [GIUSEPPE CACACE/AFP/Getty Images]

A thermometer shows -10 degrees Celsius in the western German city of Winterberg on February 1, 2012. The Siberian cold front 'Cooper' has brought temperatures as low as -15 C in some parts of the country.
- [OLIVER BERG/AFP/Getty Images]

Frost-covered trees near the central German city of Kassel.
- [UWE ZUCCHI/AFP/Getty Images]

Snow fell this week in France's south-east city of Nice, better known for its balmy climate and palm trees. The French national meteorological service predicted a new cold snap would follow.
- [VALERY HACHE/AFP/Getty Images]

A frozen waterfall in Lille, northern France.
- [PHILIPPE HUGUEN/AFP/Getty Images]

Ponies forage for food under the snow on Dartmoor, northern England. The UK's Met Office has upgraded its cold weather alert to level three, meaning "severe" conditions and possible temperatures of minus -11C.
- [Matt Cardy/Getty Images]