Why is the newly renovated sparkling pool full of algae?

The Lincoln Memorial’s reflecting pool in the US capital has turned green with algae days after it filled with water following renovations.

President Donald Trump ordered the overhaul last year, saying the pool was poorly managed by President Joe Biden.

He had problems with algae for decades. The BBC’s Jake Horton looks at what’s behind the latest crisis.

Designed by Ian Aikman, graphics by Leo Scott-Richter