The Great Depression was the worst economic downturn in the history of the industrialized world, lasting from 1929 to 1939. It began after the stock market crash of October 1929, which sent Wall Street into a panic and wiped out millions of investors.
Teacher in Rural Kentucky
Most likely in Medieval China
The front page of a newspaper, would most likely be the best, because so many people read newspapers these days. Its highly likely, many people will be able to see your ad first thing.