The first feature I noticed inside the main entrance was Rackspace's timeline - ten feet tall and sixty feet long. We've all seen dozens of these in corporate slide decks and I've made more than my share. Rackspace took theirs off the slide and put it in a prominent location, celebrating their history and progress for all to see. That is communicating leadership to their visitors and their team.
At a smaller scale this is fairly easy and relativity inexpensive to execute using a mix of techniques. In this case it appears Rackspace used printed vinyl for the year and data band at the bottom (you can see the white background) and cut vinyl for the upper elements.
Here is the Google map tour if you'd like to see the whole wall or visit other parts of the Castle. I recommend using the expand button in the upper right hand corner of the map viewer.