Balloon bombs made of paper

During World War II, Japan produced about 10,000 balloon bombs made of washi, a paper obtained from the bark of the kozo tree and made gas-tight with varnish. These balloon bombs transported incendiary and explosive devices (5 to 15 kilograms) across the Pacific Ocean to America.

However, it took 30 minutes to an hour to prepare a balloon for flight and required about thirty men. In addition, the balloons could only be launched in certain wind conditions. The first balloon bomb had its takeoff flight on November 3, 1944.

The balloon bombs were intended to cause damage and spread panic throughout the United States.
The balloons claimed six American lives on May 5, 1945, but they were considered a military failure in Japan and the project was discontinued at the end of May 1945. The existence of the balloon bombs was hushed up in the USA to avoid panic among the population.

And even today, the dangerous balloon bombs can be found by chance. In 2014, one such balloon bomb was discovered in Canada, and it was still fully functional.