Why is MIT and Harvard so close to each other? Is there any particular
reason why such prestigious universities are so nearby? Is it a better
place to expand one's knowledge because of the over-abundance of
smarter people around you? I was thinking of attending Stanford
University, but I also am aware that Harvard and MIT allow students to
take courses in the other university, and vice-versa. They are
practically less than a 5 minute ride (probably 15 minute walk) from
each other, right?

Thanks!

Boston is one of the oldest cities in the U.S.  The Boston-Cambridge
area is an educational Mecca.  Harvard and MIT are only two of many
institutions of higher education within a very small geographic area. 
Harvard is the oldest institution of higher learning in the U.S. and
was founded in 1636 by vote of the Great and General Court of the
Massachusetts Bay Colony.  MIT was founded with the aim of
establishing a new kind of independent educational institution with a
role to play in a newly industrialized society.  It admitted its first
students entered in 1865.  These two schools had very different
purposes behind their founding, but obviously it was thought that the
area could support many more than two major institutions.  Within a
few miles of one another are these two and also Boston University,
Northeastern University, Emerson College, and many more
(http://www.searchboston.com/dir/Education/Colleges_and_Universities/).
 Many of these are within walking distance or a short trolley or bus
or subway ride of one another.  Asking why they are so close together
is sort of like asking why the Washington Monument, the Capitol
building, and the Lincoln Memorial are so close together.

However, given the traffic, the ride is going to be more than 5
minutes, and I think the walking distance down Mass. Ave. from the
main gate of Harvard Yard to the front steps of MIT's most conspicuous
building is something like three miles.  I'd take the bus.

Archae0pteryx

I'd add to archae0pteryx's comment that MIT used to be further away
from Harvard than it is now.  When it was founded, it was located
somewhere in Boston, not in Cambridge.

That's just another indication that their current proximity is just
part of their history, not part of some well-planned effort to
concentrate academic excellence

Good point!  And--they're closer than they used to be because both of
them have expanded by buying up surrounding properties and adding to
their campuses.  I always kind of hoped I'd be there to see it when
they actually collided on Mass. Ave., but I live in California now.

Archae0pteryx

> Why is MIT and Harvard so close to each other? Is there any particular
> reason why such prestigious universities are so nearby? 

I will just add Harvard once consider "acquiring" MIT, but MIT's board refused.

> Is it a better place to expand one's knowledge because of the over-abundance 
> of smarter people around you? 

As a MIT alum, no. :)

> I was thinking of attending Stanford University, but I also am aware
that Harvard and MIT allow students to take courses in the other
university, and vice-versa. They are practically less than a 5 minute
ride (probably 15 minute walk) from each other, right?

The bus/car takes about 10 minutes depending on traffic.  Walking is
more like 25 minutes.