Protesters marched in Denver, Chicago and Washington on Saturday to challenge President Donald Trump’s stance on the environment and call on him to stand by policies to stop climate change championed by his predecessor.

Thousands of people gathered for the afternoon march from the lawn of the U.S. Capitol to the White House, an event that coincides with the completion of Trump’s first 100 days in office and the end of the traditional “honeymoon” period for a new president.

The Peoples Climate March, which drew about 15,000 people, according to an estimate by a Reuters reporter, rivaled last weekend’s March for Science in size.

Protesters sounded many of the same themes at both events.

Carrying signs emblazoned with slogans such as “On thin ice” and “Water is a human right,” demonstrators on Saturday said they were angered by the prospect of Trump carrying through on his vow to roll back protections put in place by his predecessors.

Trump’s administration is considering withdrawing from the Paris Agreement, which more than 190 countries including the United States signed in hopes of curbing global warming. Trump has also proposed deep cuts for the Environmental Protection Agency.

In his campaign, Trump called climate change a hoax. Last month he kept a promise to the coal industry by undoing climate-change rules put in place by his predecessor, Democrat Barack Obama.

Environmental activists believe public opinion is on their side. A Gallup poll this month showed 59 percent of Americans agreed environmental protection should take priority over increased U.S. energy production.

Trump representatives had no immediate comment on the protest.

Reuters