Before revision: The shelter is composed of 42 school buses, which were buried underground as patterns for concrete that was then poured over to provide the main structure, onto which up to 5 meters (14 foot ) of earth were piled to provide fallout protection.
After revision: The shelter is composed of 42 school buses, which were buried underground as patterns for concrete that was then poured over to provide the main structure, onto which up to 5 meters (14 feet ) of earth were piled to provide fallout protection.