No computer was fatter than the SAGE (semiautomatic ground environment) computer. It contained more than 55,000 vacuum tubes and consumed 1 million watts of power. The vacuum tubes ran so hot it was estimated that if the air conditioning failed, the SAGE would self-destruct in 60 seconds. Despite its size, a decent hand-sized calculator of today is more powerful than the SAGE.

Completed in 1958, the purpose of the SAGE was to link radar stations in the United States and Canada so that a large-scale bombing raid on North America could be detected before it happened. SAGE computers were housed in the basements of massive, windowless, blast-proof bunkers. Phone lines using devices not unlike today's dial-up modems connected these bunkers.

Reportedly, the phone bill required to connect the 23 direction centers that housed SAGE computers was millions of dollars per month, but that's nothing after you've already spent $60 billion on the computers and housing structures themselves.