The sign on the F-1 engine. It reads
A cluster of five engines like this one provided the power for the first stage
of the Saturn V launch vehicle during the Apollo-Saturn test flights, manned
flights to the Moon, and the launch of the Skylab orbiting laboratory into
Earth orbit. The engines were powered for 2-1/2 minutes lifting the Saturn V
to an altitude of about 41 miles and a speed of about 6000 miles per hour.
Each engine weighed 15,650 pounds and developed a thrust of 1,500,000 pounds.