Located near Santa Cruz Island in Channel Islands National Park, this enormous sea cave is the second-biggest in the United States and the twelfth-largest sea cave in the world. The entrance, which is submerged in 30 feet of water, is about 100 feet wide and rises 160 feet above the water. They are called "painted caves" due to the naturally occurring hues that different types of rocks, lichens, and algae produce. This cave is inhabited by marine organisms, harbor seals, sea lions, and many bird species, which makes the entire experience more thrilling. As you paddle farther into the cave, connecting chambers emerge, each with progressively less light.