The Museum is (as the name implies) is a museum. There have have been a few known of these places that have been named museum. In The Masterpiece the museum was seen but it was like an old gray type and SpongeBob took the left side of it for Squidward to use it to create the Statue of Mr. Krabs then it collapsed. In New Fish in Town this museum was like a rich home and in Squidward's though he and Howard rode their bikes on the red carpet up the stair into the front entrance to the museum.
It has appeared as a sunken dragon ship with a hole on the side with 5 pallets which seem to hold it up. This type has appeared in Atlantis SquarePantis where Mr. Krabs was selling tickets to get people to enter. Then again in Are You Happy Now? where SpongeBob and Squidward enter the museum to create Squidward's happiest moment. It was at first his happiest memory until Fiasco ruined his sculpture which was burned as he used his flamethrower to make it worse.