The Cobscook Bay tide rushes through the Mahar Point narrows so strongly, it looks like the ocean is boiling as water collides with the currents of Dennys Bay — a phenomenon known as a reversing falls. Look for eagles and harbor seals. End of Leighton Point Rd., Pembroke. 207-726-4047.
An easy mile-long hike in the Debsconeag Lakes Wilderness Area leads to a cool cave that keeps its icicles nearly all summer. Bring a flashlight to see the sparkle. Hurd Pond Trailhead, 18 miles west of Millinocket on the Golden Road. 207-729-5182.
This “cave” at Grafton Notch State Park is actually a narrow gorge 200 feet long and 50 feet deep. (Legend says it’s named for an unlucky moose that fell inside.) Access via Rte. 26, Grafton Township. May 15–October 15. $1–$3. 207-824-2912.
Up to 250 feet wide and 40 feet deep, this convergence of powerful currents in the Bay of Fundy is the Western Hemisphere’s largest whirlpool. For the safest peek, check with local ferries servicing Eastport, Campobello Island, and Lubec. Off Moose Island, Eastport.