They charge $20 regular entry, and $20 to skip. Total $40. All you do it go to the front of the line there is a limit to the number of people allowed in at one time..its self guided tour...
There are 2 lines at the front door. One side is for the people who purchased tickets online
They havr a skip line that's an additional cost. Call ahead it may be less confusing
Thanks! Your answer is awaiting moderation.