A wild secret is buried beneath this grassy hill

An extraordinary cave system is hiding in the backyard of a house for sale in the US. 

There are over 5500 square metres of underground caverns twisting and turning through this unassuming Tennessee hillside. 

The entrances to the caves are protected by over 10 tonnes of camo-patterned steel. 

Inside, the rocky ceilings reach over nine metres tall in parts.

Natural springs run at your feet all year round, ensuring a reliable water source. 

“Potential uses are endless – safe haven, private retreat, underground event space or revenue generator,” the Zillow listing for the property reads. 

Avid doomsday preppers who want to try their hand at self-sufficiency would find limitless storage space for vegetables and canned goods.

The underground cavern network is part of a larger deal for a 32-acre homestead.

The buyers will also get a brand new two-bedroom house and a separate granny flat. 

Unique features abound throughout the house, from leaf-shaped wooden ceiling fans to Italian marble bathrooms. 

A wood-burning stove warms the house during the cold North American winters. 

Outside, the grounds are set up with country living in mind.

There are fenced paddocks for cattle, patches of woodland and an up-and-running chicken coop. 

More unconventional features are also included in the sale – such as a shooting range and a Humvee military truck.

The homestead is on the market with an asking price of $US1.75 million ($2.68 million). 

“Welcome to one of the most unique and versatile properties on the market in 2025, where high-end living meets unmatched potential,” the listing by Hasty Realty reads. 

“This is more than a homestead, it is an opportunity to own something truly rare.”