well ... according to this www.nationmaster.com...
place... alot of cities have "underground" sections that make everything accessable from underground
they even call them underground cities
and it gives a list of known modern cities
ill paraphrase some of it for ya
"An underground city is a network of underground tunnels that connect buildings, usually in the downtown area of a city. These may include office
blocks, shopping malls, train and metro stations, theatres, and other attractions. An underground city can usually be accessed through the public
space of any of the buildings connecting to it, and sometimes has separate entries as well. Download high resolution version (847x318, 51
KB)Bonaventure metro station, an important link in Montreals Ville souterraine, with directional panels to buildings reachable by the underground
city. ... Download high resolution version (847x318, 51 KB)Bonaventure metro station, an important link in Montreals Ville souterraine, with
directional panels to buildings reachable by the underground city. ... An underground pedestrian tunnel between buildings at MIT. Note the utility
pipes running along the ceiling. ... For the traditional meaning of the word mall, see mall. ... Passengers bustle around the typical grand edifice of
Londons Broad Street Station in 1865. ... A metro station is a train station for a metro. ... Theatre is that branch of the performing arts concerned
with acting out stories in front of an audience using combinations of speech, gesture, music, dance, sound and spectacle — indeed any one or more
elements of the other performing arts. ...
Underground cities are especially important in cities with cold climates, as they permit the downtown core to be enjoyed year round without regard to
Underground cities are similar in nature to skyway systems and may include some buildings linked by skyways or above-ground corridors rather than
underground. A skyway is a path that is traversed without touching the ground. ... "
there is alot of photos and plenty more to read on that website i listed
also of interest :: there is a very long list of hundreds of underground cities on that webpage i listed *modern ones*
from all known nations who have these networks under certain cities
if you want more info , a good place to start would be google or www.wikipedia.com
edit::added a pic of Bonaventure metro station, an important link in Montreals Ville souterraine
[edit on 25-6-2005 by muzzleflash]