The Olympic women's synchronized 10-meter diving final is underway from Rio on Tuesday, where the water in the diving pool has inexplicably turned an unsettling shade of green.

Yesterday, the diving pool was a normal shade of blue — the same color as the other pools we've seen in the Olympics. Perhaps most odd of all, the water in the water-polo pool just across the pool deck remains a normal-looking blue.

British diver Tom Daley, who won bronze on Monday, tweeted a picture that shows the contrast between the diving and water-polo pools:

Contrast that to this look at the two pools a few days ago:

Here's the underwater camera from yesterday in the diving pool:

Diving seems hard enough when you don't have to go headfirst into this slime water. Worst of all, nobody yet knows why the color is the way it is.