Schieks Cave Below Minneapolis Contains a Lake of Warm Sewage

Deep beneath the streets of Minneapolis lies a hidden geologic anomaly called Schieks Cave, which was discovered in 1904 by a sewer engineer. The city kept the cave a secret, fearing people would think the city was built on unstable ground. Urban explorer Greg Brick was determined to explore the cave, and after years of research, he finally gained access in 2000. Inside, he found a unique smell, natural carvings on the walls, and unexpected sights like roaches and earthworms. However, he also discovered raw sewage, which was a major concern due to its potential health implications. As a hydrogeologist, Greg was intrigued by the warm groundwater, which was 20 degrees above the expected temperature for Minneapolis. He measured the water temperature and found it to be unusually warm, similar to the temperature in Jackson, Mississippi. Greg's discovery confirmed a team's prediction that heat from the urban surface was seeping deep underground, warming the groundwater. This has implications for public health, as warm water can multiply bacteria, which can then enter the pipes and affect people's health. Despite the importance of this issue, Greg has struggled to get authorities to pay attention, and the cave is now off-limits due to a law passed in 2008.