Pristine Underdark River

Publisher's blurb: Dark tunnels open up to a wide cavern, lit by a glowing blue body of water. Natural stone bridges cross above it, while schools of fish swim below; darting in and out amidst violet and red disk-shaped plants. The cavern walls are also lined with the strange growths, while purple and red tubular plants glow eerily on the walkways. Sand and crumbling stone crunch underfoot, and the fish occasionally fly out of the water; calling strangely before diving in again.