A merchant crosses your path -
"I've got nothing, I tell ya."
One day, a man was presumably walking across this rocky shoreline and found an abandoned building by the seaside. It wasn't close to anything else, there were no roads leading to it, and there was this thick, dense forest surrounding the house. He lived there for years before anybody found him and is recorded to have lived there for at least 30 years from 1986 to 2016, when he died at the age of 90. He left no known descendants.
When locals from the nearest town investigated the house, they found a part of the basement that looked like it had been heavily damaged, and then resealed with bricks. Inside, they found a hand carved cave, dug into a pocket of soft rock. The walls of the cave had been hand carved into beautiful geometric designs. In the center of the room was a small pile of stacked rocks and the ground on which it stood appeared to be charred, as if there had previously been a fire there.
It is unknown who carved out the cave, whether it be the original architect of the building, the most recent owner, or someone else entirely.
Nobody knows who built the house, or how. Today it remains unused, and although it has been repossessed by the local government, many people regularly trespass onto it in order to get a look at the ornately carved cave walls.