On July 16, 1969, a rocket in Cape Canaveral, Florida launched three humans into space, destination moon. They were hurtled away from Earth with the help of NASA's Saturn V rocket -- and with the help of, at the rocket's base, five Rocketdyne F-1 engines. This was a lot of help. According to a 1965 press release [pdf], "The F-1 is the most powerful rocket engine to be ordered into production in the United States. It is a single chamber, liquid propellant engine of conventional, proven design developing 1,500,000 pounds of thrust." And despite all the advances we've made since then in the broad field of rocket science, the F-1 remains the most powerful single-chamber liquid-fueled rocket engine ever developed.
And yet. The engines, like so many of the instruments we devise to send ourselves into space, were useful only briefly: The F-1s had a practical shelf life of about 165 seconds. After the Saturn V and its passengers had gotten the boost they needed, the engines were jettisoned: five scarred, metal cones sent hurtling into the waters of the Atlantic.