Morning fog embraces the trees of the City Park of Budapest, Hungary, Feb. 3, 2017.

Fog is seen over over the Jested mountains, Czech, Republic in January 2017.

The sun rises as blanket of fog covers the Aleppo citadel and the city of Aleppo, Syria, Jan. 20, 2017.

City of Edinburgh shrouded in frozen fog in Edinburgh, Scotland, Jan. 21, 2017.

The Eiffel Tower in Paris, France, in a heavy fog, Jan. 31, 2017.

A deer jumps through a field at sunrise in Popielarze village near Warsaw, Poland, Jan. 27, 2017.

Fog is seen over the Bavarian city of Garmisch-Partenkirchen, Germany, Jan. 20, 2017.

The Ayrton Light is seen lit above the belfry in Elizabeth Tower, commonly known as Big Ben, on Feb. 1, 2017 in London, England.

Lake Constance covered in dense fog, Feb. 2, 2017.

A pedestrian walks through the winter fog in temperatures in Berlin, Germany, Feb. 1, 2017.

A man walks in fog in Dunham Park near Altrincham in Britain, Jan. 23, 2017.

A blanket of fog covers the city of Sofia, Bulgaria, Jan. 21, 2017.

Strollers walk in the morning fog at the bank of the Danube with the Chain Bridge in the background in downtown Budapest, Hungary, Feb. 3, 2017.