In 2011, the Condit Dam in Washington State was "removed," meaning that a small portion of it was blown to pieces, allowing the White Salmon River to flow through it. The dam had been in place since 1913.
In the video below, we see two fascinating things: First, the effect of the dam removal downstream, as water floods back into what had been a dry riverbed for a century. Second, the effect upstream shows a restoration of the original White Salmon River, as the water level radically declines (shown in timelapse). The power of water is amazing.