I traveled to Spectacle Island and George's Island with some friends, departing from Boston Harbor. Apparently Spectacle Island, or Testicle Island, for short, is mostly man made, and built upon a foundation of dead horse carcasses and trash. Consequently, there was an incredible amount methane built up within the island that caused ongoing fires back in the day. Because of this, I think they should build a monument of a fossilized horse continually on fire. There are a lot of birds and things to look at, and the island offers some really good views of Boston (but no trash cans).
This is a fort on George's Island. There are all kinds of interesting tidbits about the Civil War posted, like how awkward it was for Union soliders to hang out/ play football with captured Confederate soldiers.