In the middle of a tangle of mansion-laden, suburban streets, the graffiti-covered, half-finished lava house seems a bit out of place.

Few people know how it got there, but it was the local teenagers who christened it, thanks to heaps of lava rocks strewn about the property. Built by Jerry Ganz (the fabulously wealthy man responsible for the mass production of seat-belts), the Lava House’s chief architectural pull was its extensive use of imported lava rock. Ganz faced numerous roadblocks by the city. He spent almost 20 years fighting city officials to get his architectural fantasy approved. Construction stopped only two years later after they were finally approved, and it has remained empty to this day.

The City of Tiburon has tried desperately to sell it off, even razing what was left of the structures there after a 1997 fire to attract more buyers, but to no avail. It is mostly used these days as an impromptu party locale or a haunt for photographers trying to get a good view of the Bay, but exploring the maze of steep staircases, hidden subterranean rooms, and twisting balconies is also popular, both by night and by day.