River that starts in Hopkington and dumps out into Boston Harbor, seperating Boston and Cambridge. If you go to the Charles, you will likly see some smuck floating around, maybe a few condoms and dead birds as well. People row on it when its now winter and completely frozen over. It is famous for the Head of the Charles, a huge rowing regatta with tons of teams.
It is incredibly filthy, but I have swam in it and I am still alive today.
Son: Mommy, I touched the water in the Charles River with my finger.
Mom: Oh no, let's go to the hospital.