A pilot inflates his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. According to the organizers, over 80 balloons from 20 countries are participating in the ballooning event in the Swiss mountain resort. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons fly during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A pilot checks his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons fly during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons fly during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A pilot inflates his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A pilot inflates his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A balloon flies during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A balloon flies during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons fly during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A balloon flies during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons fly during the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

A pilot inflates his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)

Balloons of all shapes and sizes get ready for take off at the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. (Photo by Pierre Albouy/Reuters)