Answer: $25 the first time ... I have been fortunate to go three times to three different locations. The first time I stayed for 3 minutes ...then got tired of hearing everyone say ... "HOW COULD YOU STAY THERE FOR ONLY THREE MINUTES?!" So years later, I came back for three more ... three more hours that is, lots to see here. I came back a third time in the west for another three hours ... where a glass-bottom observatory was built.

TRIP 1 - 2004 ... SOUTHERN RIM

TRIP 2 - 2008 ... EASTERN ENTRANCE

TRIP 3 - 2018 ... WESTERN RIM