Exactly what the title says. The Floating City of Nym, the Churning Mists, the Sea of Clouds. All massive landmasses -- the latter two more so than the first, of course -- that float, and no adequate explanation I can find about precisely why and how they're floating. Even the rocks around the first part of T6 are floating.

Maybe the Rule of Cool is supposed to be in play here, but I refuse to suspend my disbelief for this. The only floating continent that is even vaguely explained for me is Azys Lla, and that's just some technobabble with Allagan tech.

So far, the only clue I've found as to why these things are floating is the crystals they're on. What do these crystals do, and is that why they're floating?