The largest non-subglacial lake in the world is in Dragon's Breath Cave in Namibia, with an area of almost 2 hectares (5 acres), and the second largest is in Craighead Caverns in Tennessee, United States.
- Subglacial lake – A lake under a glacier
- Subterranean river – A river that runs wholly or partly beneath the ground surface
- Subterranean waterfall
Media related to Underground lakes at Wikimedia Commons