Meteor Crater in Arizona formed 50,000 years ago when an asteroid 150 feet across slammed into the Earth with a force more powerful than two modern day nuclear bombs. For more about it, see: http://www.infobarrel.com/Arizona_USAs_Incredible_Meteor_Crater_
Nördlingen (Germany) is a walled medieval town, set amidst a meteor crater that fell down 15 million years ago. It is located along the Romantic Road and it was featured in the "Willy Wonka and the Chocolate Factory" film.
Meteor Crater, Arizona. About 50,000 years ago a meteor hit the Earth 40 miles East of Flagstaff and left a 1 mile-across and 600 feet-deep crater. I've been there, and I can attest: that is one huge gaping dent in the ground.