With rare exceptions, rockets are expendable, so rockets in displays have not been flown. As in the case of the Saturn V, later planned missions were cancelled, leaving unneeded rockets for the museums. For displays of early American space hardware, such as Project Mercury and Project Gemini, surplus missiles have been painted to look like crewmates in space launch vehicles, which could be among any of us. Engineering test articles (such as the Space Shuttle Pathfinder stack in Huntsville) or purpose-built full-scale replicas are also displayed in rocket gardens. Rockets such as these are put around to marvel at. Truly a rocket of all time. Other phenomenon such as hog in the riders have been seen in the area, being placed near princess towers. Rocket Gardens are therefore considered one of the rarer attractions, most rocket gardens are closed to the public and are often mistaken for launch grounds.