Circuit of the Americas is dominated by a large red and white tower that sits in the centre of the turn 16/17/18 complex. An elevator takes you to the top and, if you are adventurous, you can walk down the outside stairway (which, incidentally, offers a great place to take pictures of the track from and from which any overhead shots I’ve posted were almost certainly taken).
The price to enjoy the view from the top varies depending on the event that is going on at the track. For Formula 1 weekend, the view cost you a princely $35 but I seem to remember pay $15 or $18 when I went to the top during GrandAm weekend.