Thousands of environmental activists marched in Washington Sunday to protest plans for the Keystone XL pipeline.
Organizers of "Forward on Climate," who planned the event, told Reuters that about 35,000 people from 30 different states braved the cold to join what they said was the biggest rally calling attention to climate change in U.S. history.
If it gets government approval, the Keystone pipeline would carry oil from Canada to refineries in Texas.
Supporters say the pipeline could create 20,000 jobs, but opponents say the environmental risk is too great.
Protesters urged President Obama to halt the pipeline plans to honor his inaugural pledge to act on climate change.
Some famous protesters on hand included actresses Rosario Dawnson and Evangeline Lilly, as well as hedge fund manager and environmentalist Tom Steyer.