The Network
Rivers in Felarya go almost entirely unexplored by typical adventurers - deemed far too dangerous to brave the perils of even the more shallow waters. However, stories do tell of a large interconnected series of underwater streams. Legends speak of treasures galore - as they often do. However, there have been a few accounts from human sized mermaids: there are a few rivers with deep, smaller crevices at the bottom of the rivers, which lead into flowing underground rivers. Its not a honeycomb, however. These under ground rivers do extend quite far throughout Felarya though, and the "treasures" are an insane concentration of water based life and flowing magic. There are some parts of the underground river that go even deeper, however - into the mysterious underbelly, the subterranean zones of Felarya. Supposedly, super giant crystals line the water, making everything glow in combination with the unnaturally bright phosphorescent plants growing on the inside. Swirling magic flows through these underground rivers almost as if it were the arteries of Felarya - the mysterious underground ecological systems draw from this magic as well, feeding into various areas.
Adventurers and most normal folk of Felarya hardly know the truth of the depth of The Network, though.
(( WIP idea ))