Shards

Shards are floating islands that hang in the skies of Yuna above the Sea of Monsters. Shards range in size from city states down to the size of dinner plates and cover every type of biome imaginable.

One of the defining mysteries of Yuna is what force lifted the Shards into the sky and what is keeping them afloat. Many theses have been written at the Scholomance about what might be the cause but as of yet no one has been able to definitively.