The entrance is free, but advanced online reservations are required.
Unique geocaches are available inside and around the city to seek out.
Souvenirs like shirts and stickers can be purchased, with some freebies for visitors.
A few nearby places worth checking next.
I have been using it now for 3 months and it saves me so much research. Reduces the need to call and double check every time.
How did I not know these places existed?! Atly's scoring is a lifesaver, now I can finally find THE spot without wasting time Googling my life away.