The Eureka Bunker was a late 1930s secret Department of War facility that predated Camp Eureka.The bunker was a massive underground facility. The facility is where the first atomic bomb was created and tested. The byproduct of the first bomb test was element X which caused the team assigned to age rapidly and they were forced to seal themselves in the lab to prevent spreading the contamination.The base has a droplock security system that seals the doors when the power goes out and cut off the oxygen. The facility has three access points including an elevator shaft in the forest, a utility shaft under Tesla High School and ventilation shaft disguised as a capped well. The facility was buried and forgotten about for 70 years until Eva Thorne returned Eureka and try to permanently seal it off.