For those who are a little less familiar with the Boston area, the Charles River separates Cambridge (to the North) from Boston (to the South) and is a hub of activity for the city. The Massachusetts Ave. Bridge links the downtown Boston area to Cambridge, and is the best spot for watching the annual 4th of July Boston Pops Fireworks Spectacular.
If you're itching to get on the water, you can book a sunset river cruise and take in the skyline from a new perspective with the Charles Riverboat Company, departing from the Cambridgeside Galleria shopping mall.
For a memorable tour that incorporates the river, there is always the Duck Tour. In their fleet of WWII amphibious vehicles, no two conductors are the same. They will take you through the best highlights on land before plunging into the river at the end of the tour. If you want to learn to navigate the river yourself, you can take sailing lessons at the Community Boating club. If it's too hot outside, you can travel on the MBTA Green Line and hop off at Science Park to take in the view from the Museum of Science, which is positioned over the river.
The Charles River Reservation is the official name of the park along the riverbanks, and contains bicycle and pedestrian friendly pathways. In the summer, when the hours of daylight are at their longest, you better believe most of the city is out enjoying the waterfront area. Once, on my walk home from work, I stumbled across an orchestra warming up at the Hatch Shell. It was so nice to pause and listen for a little while in those golden hours before sunset. Summer, to me, is all about enjoying beautiful outdoor spaces, just like the Charles River.