I just saw a great episode of "American Experience" on PBS about the Panama Canal.
Extremely well made hour-long documentary.
They were going to give up because so many people were dying of Yellow Fever which people believed was caused by unclean living conditions.
They brought in some doctor who was convinced it was a mosquito-bourn malady, but his eradication program was considered too expensive, and many didn't even think he was correct in his mosquito theory.
Teddy Roosevelt's personal physician convinced him to order that the doctor be given everything he needed to eradicate the mosquitos.
He was, and he did. They actually travelled the entire length of the canal, fumigating and pouring oil into puddles and swamps to trap the larvae.
They wiped out Yellow Fever entirely, and the project was able to continue. But that was just one amazing aspect of the canal. The actual digging was brutal work, and then the "water stairway" system they devised was just ahead of it's time. Fascinating stuff.
It's a shame you guys can't get PBS over there, it's some of the best television we've got here.