In 1919, German crews sank their own fleet at Scapa Flow. 100 years later, its steel became prized by industry for being radioactive-free

In 1919, German crews deliberately sank much of their surrendered fleet at Scapa Flow rather than allow the ships to be divided among the Allied powers. Most of the 52 vessels that went down were later salvaged, but seven remained beneath the Scottish waters. Decades later, their pre-1945 steel gained unexpected importance because it had been produced before atmospheric nuclear testing introduced radioactive contamination into the environment.