Electronic cleanroom in Vietnam. (BSLtech)
Cleanroom project in Algeria. (BSLtech)
Glasgow Central Low Level, 2008. (geograph.org.uk)
Rotational slump along the Red River in north Fargo. July, 2000. (ndsu.edu)
Two zones of fissuring resulting in vertical displacements in the region of N 10th Street, Fargo. March, 2000. (ndsu.edu)
Photo by Dave Bunnell of the Chandelier Ballroom in Lechuguilla Cave. These are the largest known gypsum stalactites in the world. Each is tipped with a spray of gypsum crystals.
Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest (1,604 feet or 489 meters) in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition.
Source: Wikipedia
The Moon's cosmic ray shadow, as seen in secondary muons detected 700 m below ground, at the Soudan 2 detector
Source: Wikipedia