Sunset on Walden Pond, made famous by writer Henry David Thoreau | John Greim/LightRocket via Getty Images

Pollution Is Transforming Thoreau's Once Pristine Walden Pond

Sediment samples reveal swimmers and tourists are polluting the lake where Henry David Thoreau sought solace in the mid-19th century. And climate change is expected to exacerbate the damage.

Published On 04/05/2018
1:43 PM EDT