How long did it take to build the first hot air balloon?

The first hot air balloon was built by the Montgolfier brothers, Joseph-Michel and Jacques-Étienne, in 1782. Their initial experiments began in the early 1780s, culminating in the first successful flight of a balloon made of paper and linen in September 1783. This balloon was launched in Annonay, France, and marked the beginning of human flight in hot air balloons. The entire process from conception to the first flight took about two years.