U.S. unemployment stayed in the double digits -- in other words far worse than the more recent Great Recession -- for all of the 1930s, according to estimates.

It wasn't until the U.S. entered World War II and ramped up industrial production and military service that unemployment return to more normal levels.

In this photo, a partially-paralyzed man lays on a cot with his dog sleeping underneath in May's Avenue camp, Oklahoma City, Oklahoma.