At its top, the Tower of Pisa is 15 feet out of alignment with the bottom, in danger of tipping over. But the lean is being painstakingly corrected. It’s “a delicate operation in which dirt is being extracted through thin drill pipes— the geotechnical equivalent of laboratory pipettes— from under the north, upstream side of the tower foundations, allowing it to settle toward the upright direction. The rate of soil extraction amounts to just a few dozen shovelfuls a day; anything faster might jolt the tower over the brink.” – Discover Magazine