A small beach with easy entry. Several lava tubes may be found a short swim to the left. There is a nice and cave off to the left of the cove with easy entry and exit. The rocky beach has a semi-trail down to the water's edge - only a few meter from the road to the water. One of mother nature's wonders, a large archway cavern back lighted with a shaft of light coming from a skylight between the arch and cavern, awaits your exploration. The bottom is quite rocky as you go out, so watch for reef fish immediately. Snorkel out about 45 meter (to conserve air), then dive to the bottom, which will be only 4 to 6m down. Explore the reef there. Turn left (south) and cruise along the bottom with the reef on your left. After about 45 m you'll come to a sandy channel that heads toward shore. Follow the channel into a crevice in the lava and coral shelf. To your right and left, as you head east (or toward shore) you'll see many nooks and pukas (holes) in the walls of the channel. Within a few meters directly ahead there is a large cave with a sandy bottom. The cave is about 1.5 to 2.5 meters long but is exiting. On the other side is another cave. Continue through the tube until you see the chimney that leads to an opening very near the surface. The bottom of the chimney is about 75 m deep, with the opening at less than 3m from the surface. When you reach the top of the chimney, depending on the tide, you'll find yourself in shallow water - on a flat ledge - that is but a few feet off shore. Watch the surge. Continue away from shore, over a smooth sandy bottom for about 25 to 45m. You'll come upon a coral and rock outcropping that is teeming with reef fishes. Bear north along this mound of stone and coral for about 45 to 65m, then head toward shore. Directions: Mile Marker 4 is, as the name implies, found right at the 4 mile marker of Ali'i Drive just south of Kailua.