20. Pittwater High School

Location: Sydney, Australia

Year of Fail: 1986

In the 1960’s architect Dante Bini developed a technique that involved laying concrete over a balloon of plastic to create a domed structure called a “Binishell.” One such structure was located in Sydney and housed a high school. In 1986, just minutes after students had filled the building, the dome completely collapsed. An error on the first night of construction was chiefly responsible: One of the blowers used to keep the dome static was accidentally shut off, causing the concrete to buckle. Noticing the error, the chief engineer built a concrete cap to strengthen the dome, but the extra load only served to contribute to the cave in.