The Sudbury Neutrino Observatory (SNO) in Canada is a scientific masterpiece. Designed for astrophysics research, the sphere measures 40 feet in diameter (12.2m) with a thickness that varies between 2 inches (5cm) and 4 inches (10cm). Constructed in a clean-room environment 1.25 miles (2km) beneath the earth’s surface, more than 1,550 feet of bonds (470m) were required in the construction of the structure.

Because it was built in an old mine, the clean room environment was left in place to prevent mine dust from affecting the integrity of the readings. This observatory has provided revolutionary insight into the properties of neutrinos and the core of the sun.