A LiDAR scan can reveal ancient Maya ruins that might never be found by archaeologists on the ground.
They are finding tons of new earthworks in the Midwest from the Adena times (2,000) years ago. It is giving much more precise locations and allowing researchers to line the sites up with astronomical positions in the sky. One thing that I find fascinating, is that the belief the Adena believed the souls of the dead were associated with bird migrations and the mounds and earthworks seem to support that theory.