The Milton-Madison Bridge stretches across the Ohio River. The 0.6 mile long structure connects Milton, Kentucky and Madison, Indiana. It was built in 1929. The bridge has shown its age, so engineers erected new pylons. Then, carefully, they slid the entire bridge over on to these new pylons. Watch this amazing time-lapse video showing the event.
-via The Presurfer
Edited 4/28/14: Thanks for letting us know about trusses vs. pylons, Jeff!