This is turning into a tradition (see my blog posts from July 28, 2014 and July 16, 2013). Last weekend, I participated in the annual swim in the Charles River. See picture below (if you have good eyesight, I am the guy waving near the edge of the swimming area). Every year I am reminded how nice of a river we have in our backyard. And its swimmable! I hope someday we can jump in whenever we want.
All you ever wanted to know about swimming in the Charles:
http://www.thecharles.org/projects-and-programs/swimmable-charles/