Hot air balloons cross over the Alps on the opening day of the 39th International Hot Air Balloon festival in the skiing resort of Chateau-d'Oex, Switzerland, Jan. 21, 2017. Dozens of balloons from 15 countries are participating in the festival taking place from Jan. 21 to 29. Between 20,000 and 40,000 people are expected to attend over two weekends, according to the organizers.(Photo/Agencies)
