Requisitioned from farmers, blitzed with anthrax-laden bombs in the 1940s, and made inhospitable to human and animal life for decades, the tiny Scottish island of Gruinard now serves as home to a flock of healthy sheep and a disreputable monument to the birth of biological warfare. The research conducted at Gruinard during the second World War was the very first of its kind, providing proof of concept of a natural microorganism that could be massively weaponized to inflict environmental damage and human fatalities.