United States of America
The Thumb Area Bottomland Preserve, also called the Thumb Area Underwater Preserve, is a preservation area in Lake Huron in the U.S. state of Michigan. It is 276 square miles (710 km2) in size and is located off Michigan's Thumb north of Detroit.
Listen to the audio guide for Thumb Area Underwater Preserve Free on WIP — starts by itself when you arrive, even with the screen off