What you're seeing are the remains of the Aerojet-Dade rocket manufacturing plant, built in 1963, deep in the Everglades. "Space Miami" documents how the people there hoped to put a man on the moon, and how those hopes were dashed.
It's amazing to see their efforts, and it's a shame that they went to waste. The solid-fuel rockets they built were tested in a 150ft deep hole, the deepest in Florida. But the liquid-fuel Saturn rockets were eventually chosen, and Aerojet lost their contract. They then abandoned the factory. This is all that's left. [Vimeo via BoingBoing]