Wolf House, Stone ruins in Glen Ellen, United States.

Wolf House is a roofless stone ruin near Glen Ellen, California, built of dark brown and black volcanic rock set in mortar, with Coast Redwood logs, concrete and blue slate. Two levels of rectangular window openings pierce the long left wall, and two rough chimney stacks rise above it, the left one taller and more broken. The 26-room, 15,000-square-foot mansion was never occupied.

Construction began in late 1910 under Italian stonemason Natale Forni, with architect Albert L. Farr's design using local redwood, volcanic rock, blue slate and concrete. The house burned on August 22, 1913, before the Londons moved in, gutting the interior while the masonry walls stood. Steel bracing was added in 1965.

The residence embodied Jack London's vision of blending artistic craftsmanship with natural materials found on the property. Visitors walking through the remains can observe how the writer's personal philosophy shaped every structural choice.

The ruins are accessible through Jack London State Historic Park and can be explored on marked pathways. Sturdy footwear is recommended since the ground is uneven and terrain varies throughout the site.

The 1995 inquiry, led by retired San Jose State engineering professor Robert N. Anderson with ten experts, ruled out arson, lightning and an electrical fire because the generator had never been installed. It named spontaneous combustion of linseed oil finish being applied that day to the oak and walnut cabinets as the likely cause.