In medieval Greece, the monks of the ancient Byzantine Empire found themselves under attack by pirates and other undesirables. They built the monastaries of Meteoras to counter this threat. They are a series of fortified monastaries built on the tops of mountains and rocks, some thousands of feet up with no way to reach them but rope or ladder. These monks have lived in the cracks, caves, and hollows of these rocky abodes for hundreds of years, outlasting the Empire that created them. They are still occupied to this day.