Rihanna -- Loves That Dirty Water Down in Rio

Rihanna partied so hard at the World Cup … even a little poopy water couldn't stop her good times.
For some reason she took a dip at Urca Beach where pollution is so bad, people usually can't go in the water.

And yet, RiRi frolicking in a fecal tide wasn't the strangest part of Rio's festivities … for some people.