The weirdest WWII story you've never heard

Slate writes about the only fatal Japaese attack on the mainland U.S. and its implications for wartime censorship.

Improbable though it may sound, from late 1944 through the spring of 1945, the Japanese launched more than 9,000 balloons from their nation's eastern shores. Filled not with mild-mannered hot air but extremely flammable hydrogen and armed with incendiary and antipersonnel bombs, the balloons rode the jet stream across the Pacific Ocean for several days before landing throughout North America.