The islands of the sky. In those latitudes, the ocean forms a mountain,
and at the top of that mountain floats the floating islands of the sky.
It's like living in a sea-going Denver, with its thin air and cooler
temperatures. Every 16,000 years, the islands drop into the sky, for it's
really just a big droplet slowly forming over the centuries, there on the
underside of the earth, like a perpetual tear. So the previous islands
hurl into the sky and all their arts and culture are lost...unless
they're smart enough to have figured out the nature of their islands and
have emigrated by then. You'd be surprised how many don't.