Hot air balloons were originally invented to observe and predict the weather. Then they were used during the Civil War for reconnaissance and intelligence. Today, they are used purely for pleasure. Where I live, hot air balloons go up every morning and every evening in the summer. They go up so people can view the sunrise and sunset from an amazing perspective.
Every summer, I know summer has begun when I hear the jet of the gas and the burn of the flame in the morning, as the first balloons go up to view the Summer sunrise. It is an excellent sound and an awesome feeling to know that it is going to be warm and sunny for three months. I love Summer!