Off-Ramp's Kevin Ferguson goes underneath the home of Jeffrey Hildreth, where he's been digging underground for over six years. CLICK THROUGH for Kevin Ferguson's photos of the project!

The Hildreth's Sierra Madre home when they moved in.

The Hildreth residence today.

Jeff Hildreth standing at the front yard entrance of the Sterling Oak with Jack, his great dane.

Jeff Hildreth with neighbor Dave Kepple.

The Hildreth's kitchen, converted to be commercial grade.

The cavern's backyard entrance.

Inside the hole, looking at the backyard entrance.

A shot of the inside of the Sterling Oak project consisting of steel reinforced concrete. Eventually, Jeffrey hopes to reinforce the entire structure in the same fashion.

One of the mysterious elixir bottles found by Jeff Hildreth underneath his house.