Hyperinflation is when prices rise so rapidly that currency loses its value. It often occurs during times of war or internal strife. The problem usually becomes worse when governments respond by printing more money.
On his website, Thayer Watkins of San Jose State University gives the maximum monthly price increases during some of history’s worst hyperinflation crises. These include Hungary in 1945-1946, when prices rose 4.19 quintillion percent; Greece in 1943-1944, when inflation was 8.55 billion percent; and Germany in 1920-1923, with monthly price increases of up to 3.25 million percent.
In 1993, the Serbian government printed a 500 billion Serbian dinar bill. The largest denomination banknote ever officially issued for circulation was in 1946 by the Hungarian National Bank for the amount of 100 million billion pengő. Sometimes bills were just stamped to indicate denomination changes because new bills would be obsolete by the time they were printed. http://www.answers.com/topic/hyperinflation