Mauna Kea is 'only' 13,796, but from its base on the ocean floor, the big volcano measures about 43,000 feet, easily the tallest mountain in the world. From the trailhead at the top, the summit can be achieved with a mere half-mile, round-trip walk, but this is a tough half-mile when you drive up from sea level. Altitude sickness is an issue, especially for those who don't spend an hour or so at the Onizuka Visitors Center about 8 miles down the mountain at 9,300 feet.

A shrine marks the top. Hawaiians called the summit, Ka Piko o Kaulan o Ka Aina (The Famous Summit of the Land) and also Wakea's Mountain, the mountain begat by god of all the heavens. Just down from the summit are deposits of volcanic glass, similar to obsidian, which was gathered to make cutting tools and spear heads.

About a dozen deep-space telescope are built across the saddle from Mauna Kea. A demand for more observatories has created a conflict with preserving this ancient Hawaiian site. So far, the summit itself remains undeveloped.

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A four-wheel drive vehicle is recommended, and sometimes required, for the stretch of road past the visitors center. Tour shuttle buses also bring visitors. It is an unforgettable journey. Hawaii the Big Island Trailblazer has more details for planning a trip.