During a major hot-air balloon event at the French town of Hagéville, 456 hot-air balloons took off within one hour. The balloonists tried to break the world record. But that wasn’t enough. Two years ago, exactly as many balloons went up in the air at the same time. And so the record from 2017 is not broken, but equaled.
To be able to fly with a hot air balloon, the balloon must first be filled with air. Therefore the bottom of the balloon is always open. As long as the air in the balloon is warm enough, it can float. But when the air cools down, the balloon will go down. During the flight, the air is constantly heated, so that the balloon can stay in the air.