Barton Creek flows through the Maya Mountains, boring a 4.5-mile-long passageway of sculpted limestone, crystal formations, and eerie silence.

Paddle your canoe into the cave’s yawning mouth. Turn on your headlamp and illuminate this dark otherworld, where stalactites reach down from high ceilings and the only sounds are made by your paddle dipping into calm water.

Your light plays on sparkling crystals as your private guide explains how ancient Maya ventured into these same passages for sacrificial purposes.