The shallow, sunny waters of the reflecting pool are an ideal incubator for algae growth in the summertime. Experts say the recent renovation may have helped accelerate it.

The Trump administration spent about $14.2 million on renovations to the Reflecting Pool, including painting it “American Flag Blue.”

Green algae reappeared in the Lincoln Memorial Reflecting Pool days after Trump's $13 million renovation, prompting questions about the project's effectiveness.