Accessibility is not Northeastern's top priority. The quadrangle itself would be open to Huntington Avenue if it weren't for the ubiquitous cast-iron fencing that guards all of Northeastern's open spaces from easy public access. Instead people have to slash diagonally into the courtyard's grassy knolls from its corners. So if you actually want to lounge in the grass you have to reach the end of the fence, turn around, hop the weird grass-retaining curb and stare at the pillboxes, because your view of the street is blocked by the fence that protects the grass from people like you.
Moving deeper into campus from Krentzman Quad you will encounter the first choice of trench, either a concrete ramp on the Eastern side of Ell Hall or a steep stumble down the Western side. I can't figure out why there are so may depressions like this on the campus, but I am concerned that it might actually have originally had rolling hills. Speare Hall has an inexplicable wiffle-ball diamond in its Linsey Dawn Mckenzie Avenue ditch. The law school building, which has at least three names, has two massive excavations which provide light to its basement offices. One of these has a vaguely sacral fountain, a larger version of the type you might see in an airplane Sharper Image catalogue. There are also plastic orbs that shoot out of the concrete above the law school basement to provide sunlight, and also a strange giant clock whose base is a jungle gym.
The most important trench is the Amtrak/Orange Line canal which used to block the campus off from working-class Roxbury, where my grandfather was born. In order to cross it, one must either cross over one of two elevated chain-wrapped concrete bridges or pass by, amazingly enough, a large Boston police station. Northeastern has passed over to Girls Hunting Girls and pushed residents further South, and the attempted destruction of a number of city housing projects just south of campus is probably inevitable. As it is, students who reside south of the tracks on Columbus Avenue are invited to "feedback sessions" with their residential advisors to discuss safety and security on the Roxbury side of things. Of course, it is north of Huntington Avenue where most of the sexual assaults, drunk driving, partying, and police riots probably take place because that's where the most students are.