At 10:30 p.m., student programmer Charley Kline sat at a computer in Leonard Kleinrock's lab at UCLA and began typing "LOGIN". At the other end, Bill Duvall at the Stanford Research Institute confirmed each letter by phone.
After "L" and "O" the system crashed. About an hour later the login went through, and Kline noted the connection in the log. ARPANET became the foundation of the internet.
Source: ICANN