This is something you don't get to see every day. After a huge explosion, a dam which helped power 7,000 homes for almost 100 years was partially destroyed - so that salmon can swim freely down a river. Demolition crews detonated explosives in a drain tunnel at the base of the 12-story hydro-power Condit Dam, on the White salmon River in the Pacific Northwest, that's in the state of Washington.

Get a look at the explosion after the jump.

The dam's owners,  PacificCorp, chose to spend $32 million destroying the 125ft structure, in Washington's south Cascades, rather than install a $100 million fish passageway that regulators said was needed to protect wildlife.

Within two hours, water from Northwestern Lake above was freely flowing through the gaping hole, flooding the waiting river bed at its base. The lake was expected to take six hours to drain.

The wildlife they're talking about preserving are Chinook Salmon. The dam, built in 1913, blocked native species of Pacific salmon and other fish that mature in the ocean and return to rivers to spawn. It appears the goal is to return the landscape to the way it was before they built the dam. That means, what's old becomes new again, or something like that.

Watch the dam topple in the video below.