The Geo Quiz takes us to British Columbia, Canada. We're looking for a body of water there, a sound. The mouth of this sound is roughly 40 miles northwest of Vancouver at the Strait of Georgia and it ends at the town of Squamish.
This body of water was almost devoid of aquatic life for decades because of pollution from a nearby copper mine.
Run-off contaminated the water and killed fish and vegetation, even after the mine was shut down in 1974 but local communities fought for a clean-up.
And after years of legal wrangling, they got action. Their government and some of the mining companies came up with 60 million dollars to open a water treatment plant.
Today, the sound and nearby Britannia Creek are bouncing back. Herring, Pink Salmon, trout and other marine life have returned.
So what's the sound we're talking about?
The answer is Howe Sound.
Mark Angelo is Chair of the Rivers Institute at the British Columbia Institute of Technology in Burnaby, BC. He says when he first saw Howe Sound and Britannia Creek back in 1974, they looked like dead zones.