hot air balloon

People are seen watching hot air balloons fly overhead during a two-day international hot air balloon festival in Eshkol Park near the southern city of Netivot, Israel

Amir Cohen/Reuters

People are seen watching hot air balloons fly overhead during a two-day international hot air balloon festival in Eshkol Park near the southern city of Netivot, Israel

TOPSHOT - An international hot air ballo...TOPSHOT - An international hot air balloonist makes a final check before inflating during the International Hot Air Balloon Fiesta in Putrajaya on March 11, 2016. The event is taking place from March 11 to 13.  / AFP PHOTO / MANAN VATSYAYANAMANAN VATSYAYANA/AFP/Getty Images

Manan Vatsyayana/AFP

An international hot air balloonist makes a final check before inflating during the International Hot Air Balloon Fiesta in Putrajaya

A hot air balloon flies against the sun rise during Lucknow balloon festival in Lucknow, India

Rajesh Kumar Singh/AP

A hot air balloon flies against the sunrise during Lucknow balloon festival in Lucknow, India

Hot air balloons float over Bristol after taking off from Greville Smyth Park, Bristol in preparation for the Bristol International Balloon Fiesta 2013, which will see balloon pilots from all over the world gather in Ashton Court Estate for the four day festival.

Ben Birchall/PA

Hot-air balloons float over Bristol after taking off from the city’s Greville Smyth Park, in preparation for the four-day Bristol International Balloon Fiesta 2013.