Coral Castle is a toehold for man's ingress into the lush, radioactive wilds of the Foreverglades. Its construction allegedly utilized long-lost 20th century super-science, which contributes to its relative safety from the rampant plant growth.
Coral Castle was the life's labor of a single man, a Latvian immigrant named Edward Leedskalnin. He began building Coral Castle (which he originally called Rock Gate Park) outside Florida City in 1923. He would continue working on it until 1936 when the encroachment of developers spurred him to move the castle to protect his privacy; a process that would take three years as he moved the structures bit by bit to the Homestead area. He continued to work on the castle until his death in 1951. The castle proved to be an enduring attraction for tourists, and it inspired debates as to whether Leedskalnin had, as he claimed, unearthed the "Secrets of the Pyramids," that allowed him to shape and move giant slabs of coral with no heavy tools or equipment; or if he had simply concealed his use of them.
Being a mere tourist attraction in a relatively rural area, the Castle escaped the war unscathed. Its sturdy construction weathered time and the elements well enough, even as the Everglades mutated into the ever-expanding Foreverglades. Curiously, though the castle isn't on any kind of high ground and possesses no obvious means of deterring plant growth, the Foreverglades grew around the castle and left its interior spaces and courtyard alone. Other than some flooding, nothing in the castle obstructs exploration; even the ambulatory, carnivorous plants of the Foreverglades don't enter. Whatever the cause, these curious traits allow explorers to use the castle as a campground when exploring the dangerous territory.