When it comes to larger-than-life homes, an $11.8 million mansion in Lake Quivira, Kansas may have won the jackpot. Dennis Langley, a natural gas businessman, built the main portion of the home and guesthouse in 1993. His passion for scuba inspired him to expand the estate over the next three years with water tunnels under the home and through the mountain surrounding the property.

Now stretched over 15 acres of land, the luxe estate has everything from scuba diving tunnels to a 20-foot waterfall. It is an adventurer’s dream, but to truly appreciate it, you need to take a closer look inside.