Boston University, located on the banks of the Charles river, provides the average visitor with a new perspective. Its fairly easy to get to via Boston's public transportation system (The "T"). The campus stretches about 2 miles along the banks of the Charles River.
While walking this stretch, it would behoove the visitor to check out the many types of architecture that is found on Bay State Road provide a good example. These are centuries old brownstone buildings which have been converted into specialized dormitories and administrative offices. You will also be able to see "The Castle," a tudor revival mansion.
Commonwealth Avenue provides a few points of interest: The Marsh Chapel with its dove sculpture in front. and the new School of Management with its quasi-modern architecture.
Most of the buildings are open to the public, but I would personally recommend doing this during the weekday.