John McDonogh High School

Marvin Thompson knew he faced a difficult task when he was hired last year as principal at John McDonogh High School in New Orleans.

"The day that I pulled up to this building, I thought it was condemned," Thompson says.

The structure, built in 1898, was sagging and leaky and missing entire window panes. Inside, students were underperforming academically.

And then, there were the rats. Thompson and his two children didn't even finish unpacking his office before they discovered that problem.