The orange tank, weighing 65,000 lb (29,500 kg) and 154 feet (47 meters) in length, is the only one of its kind. It was never used in a shuttle launch, which would have blown it to pieces.
The California Science Center called the parade of the fuel tank, which stands about three stories tall when towed on its side by a truck, "ET Comes Home," in a play on the "external tank" name and the 1982 movie "E.T. the Extra-Terrestrial."
The tank, ET-94, arrived at the center after a 16-mile (26-km) journey, the center said on Twitter. Its arrival capped a trip that started in New Orleans aboard a barge that passed through the Panama Canal and docked at Marina del Rey on Wednesday.
The transport was a sequel of sorts to the 2012 mission to tow Endeavour from the Los Angeles airport to the science center, a feat witnessed by 1.5 million.
Crowds were smaller this time, but rows of spectators and children in homemade astronaut helmets lined the curbs along the route to see the tank pass and pose for selfie pictures with it. A dozen US astronauts, including Garrett Reisman and Sandra Magnus, made appearances along the journey.
"It's been a very smooth ride," said Science Center spokeswoman Shell Amega.
The tank is longer than the Statue of Liberty from torch to the feet. But it is neither as wide nor tall as the space shuttle, allowing it to squeeze more easily through the streets of the second-largest US city.
At various points, light poles were swung around to allow the fuel tank to pass.
The US National Aeronautics and Space Administration (Nasa) donated the tank. It was designed to carry propellants to thrust a space shuttle into orbit and then detach before disintegrating as it fell to the ocean.
© Thomson Reuters 2016