Ilaria and J's Photo Page   Acadia National Park 2007   Ilaria's Page  J's Page
thunder hole acadia foam
There's a small cave under rock that fills with water really fast causing the air inside to come out with a BOOM. However, we really only heard little belches while we were there.

What are the odds of a Thunder Hole and a Bubble Rock in the same park? Pretty unlikely, that must be why this is a National Park (and the only National Park in New England at that).