While visiting some epic 3D printing folks in Maine, they took me to Acadia National Park. On the docket for sites to see was… Thunder Hole!

From Acadia National Park website (https://acadiamagic.com/ThunderHole.html):

“Thunder Hole is the place in Acadia National Park to experience the thunder of the sea against the rocky shores of Maine! On calm days you may wonder what the fuss is all about. But wait until the waves kick up a few notches. Thunder Hole is a small inlet, naturally carved out of the rocks, where the waves roll into. At the end of this inlet, down low, is a small cavern where, when the rush of the wave arrives, air and water is forced out like a clap of distant thunder. Water may spout as high as 40 feet with a thunderous roar! Hence the name: Thunder Hole.”