The Sea Lion Caves is located a few miles north of Florence, Oregon. It's a paid tourist attraction, complete with the typical gift shop, but definitely worth visiting once if you're in the area. Here's what Wikipedia has to say about it: "The cave system is at sea level and the ocean continually washes into the main cavern which has a floor area of about 2 acres (0.81 ha) and a vaulted rock dome about 125 feet (38 m) high. Southward from the main chamber, a low passage runs 1,000 feet (300 m) to a sea level opening. This corridor is flooded at high tide and free of water at low tide. The western entrance is a short, high passage through which the ocean washes at all tide levels. At the north, a third entrance is about 50 feet (15 m) above the ocean which serves as an elevated observation area where the entire underground cave system and its wildlife are visible. Lichens, algae, and mineral stains cover the cavern walls with greens, pinks, purples, buffs, and reds on the rough surfaces some of which are named Lincoln's Head, the Indian Maiden, and The Goddess of Liberty. The sea level portion of this cave and the sea cliff rocks just outside the cave have become, over the centuries, the only known mainland rookery and hauling area (wintering home) of the Steller's sea lion and—to a lesser extent—the California sea lion. The high vault is a natural resting place for sea birds. Many birds make their home at or near the Sea Lion Caves such as the pigeon guillemot, Brandt's cormorant, western, herring, and California gulls, tufted puffins, and the occasional hawk or bald eagle. Sea Lion Caves is one of the great sea grottos of the world, comparable in size and coloration to the famed Blue Grotto in the Mediterranean." Please zoom.