At 550 feet deep and 2.4 miles in circumference, the Barringer Meteorite Crater is the best-preserved meteorite impact crater on Earth. The meteorite, which is estimated to be roughly 150 feet in diameter, was traveling at 26,000 mph when it slammed into the earth 50,000 years ago. Within seconds, more than 175 million tons of rock had been displaced, leaving a gaping crater. Today, you can stand on the rim of the crater (there are observation decks and a short trail) and marvel at the power, equivalent to 20 million tons of TNT, that created this otherworldly setting. So closely does this crater resemble craters on the surface of the moon that in the 1960s, NASA came here to train Apollo astronauts.
On the rim of the crater, a museum has exhibits on astrogeology and space exploration, as well as a film on meteorites. On display are a 1,400-pound meteorite and an Apollo space capsule. Throughout the day, there are 1-hour hiking tours along the rim. If you can make time for one of these informative, not too strenuous sessions, you should.