Drive through a volcano
It might not be exactly what you're picturing, but the Sulphur Springs Park is a volcanic crater filled with bubbling water and steam rising from the earth. It's not due to erupt anytime soon, and cars can drive right through this eerie tropical moonscape. It’s also home to a hot springs and mud bath, popular with daytime visitors.
Snorkel through Champagne
At the famous Champagne reef in Dominica, bubbles forced up through the reef by a nearby volcano make you feel like you're snorkeling through a glass of Champagne. As you float atop one of the hundreds of springs on the reef, tiny bubbles tickle your skin as colorful marine life swims by.