The shadow to the NNW of Devil's Tower, Wyoming is what caught our eye. It's right in the center of this Landsat 5 image. The tower itself is 1,267 feet above the surrounding area. The shadow is nearly twice that at 2,330 feet.
Landsat 5 captured this image on January 12, 2010.
Full images can be found on the LandsatLook Viewer. landsatlook.usgs.gov.