At mile 17.5 on Hwy 378, inside Haleakala National Park, you'll want to pull into the parking lot on the right side of the road. The elevation here is around 8,800 feet. Cross the road on foot and take the short trail to the overlook for a panoramic view of the vast crater of Haleakala. Many folks don't even notice this location because at first glance, even along the trail, it appears nothing is here. Don't make that mistake! You'll notice that the view is very close to a more distant location, the moon. In fact, NASA has used this area for just that purpose. The astronauts that landed on the moon trained here.This gigantic depression is 7.5 miles long (east to west); 2.5 miles wide, and 3,000 feet deep. This crater is so massive that the entire island of Manhattan could fit inside. From the lookout you could gaze at the rooftops of the skyscrapers. You'd swear nothing was here until you hiked down the short trail. Then, suddenly, this scene pops into view before you.
Sometimes in the late afternoon, clouds stack up inside the crater and block the view from this location, but don't fret because you might be in for another treat. If this occurs and the sun is behind you, look into the cloudy mist directly away from the sun. You may be one of the lucky people who are able to see the phenomenon labeled as the 'Specter of the Brocken.' Native Hawaiians often will call it the Ho'okuaka, a view of the soul. Around your shadow in the mist will be a halo of rainbow colors. This same spectacle can sometimes be seen from an airplane window if you are looking down on a cloud top. An apparent rainbow encircles the shadow of the plane. This phenomenon is caused by the small spaces between the cloud droplets (diffraction) rather than by the bending of light rays within the droplets that form a rainbow (refraction). Make note of how the vegetation has changed from near Park Headquarters at the 7,000 foot elevation where you entered the park. Where you once observed mostly low bushes and a sprinkling of lava, at nearly 2,000 feet higher the landscape has become mostly exposed lava and cinders with scarce patch.