Sure, Mount Everest is the tallest mountain in the world, if it measured in the the traditional sense (height above sea level). But, if height below sea level is counted, Mauna Kea, on Hawaii's Big Island is king. That is because the dormant volcano's base is almost 20,000 feet beneath the waves, meaning the height from base to summit is almost 33,000 feet, 4,000 more than Everest.

Of course, it is not up to me to dub Mauna Kea the world's tallest mountain. It is Hawaii's tallest, no one would argue that.

If climbing mountains seems beyond your reach, then Mauna Kea is for you. Because it is a typical volcano, its sides are not very steep, making it possible to drive within a quarter mile of the summit. What's not to like about that? You can stand atop the tallest mountain (base to summit) in the world while your latte sits in you cars cup holder a few hundred yards away.

It is recommended that you stop along the ascent to acclimatize. Even driving, people can sometimes experience altitude sickness. There is no need to pack your bottled oxygen, though; you'll more likely need a bottle of aspirin (and a trip to lower elevation) to cure any discomfort.