The tour of Kennedy Space Center...

includes a stop at the Vehicle Assembly Building, one of the largest structures in the world, where spacefaring craft from Saturn/Apollo to the space shuttles have been stacked for launch (click images to enlarge):

Nearby is a display of an actual Saturn V launch vehicle, and the business end of the booster is gigantic.  That's my niece and nephew standing below the enormous engine bells:

The scale of the first stage is impressive, and these images do not begin to do it justice:

At the top of the 363 foot high three-stage stack is the command and service module:

While at the center I suited up, but NASA security didn't let me near the shuttle: