Since the Big Island is the most recent, and still active volcano there is lava everywhere. It is fascinating! We saw lava tubes, fields, etc. all over the island, then went to the active volcano and saw other, freakier, looking things like this lava vent:
Another amazing experience we had there was snorkeling - not just because of the beautiful fish, but we actually got to swim with dolphins! In the wild! In this picture below you can see my mom's blue fins, and Ryan's green snorkel, and the dolphins right beyond where they are. I can't really describe just how much fun/how amazing this was!
Sean and I watching the others snorkel
We rented a boogie board with a window in it and both kids enjoyed seeing some of the beautiful tropical fish. And they looked pretty cute on the board :)