well, frankfurt is definitely not in b-w, but since you mentioned it...

in frankfurt the IG Farben-Haus by Hans Poelzig is incredible. It's been renovated to be the headquarters of Frankfurt University and has some of the few remaining Paternoster elevators in the world. also there's a cafeteria across the back plaza that's part of the same complex where you can get a good student cafeteria meal for super cheap, especially if you can convince them you're a student there.

in darmstadt, very close to frankfurt, check out the Mathildenhoehe with buildings by Peter Behrens and other greats from the Jugendstil era.

also in darmstadt, hundertwasser's Waldspirale is very interesting too.

great stuff.. the waldspirale is out of this world!

also in frankfurt (google these yourself)

OM Unger's German Architecture Museum

The Oberfinanzdirektion (an interesting 1950's office building with an incredible staircase, if you can get in past the security guard)




in karlsruhe you should check out the Center for Art and Media (zkm.de)

in stuttgart there's probably some remnants of the weissenhofsiedlung but i've never made it there myself.

freiburg/vauban on this thread

what to see in stutgart

i'd rec a short jaunt down to basel, which is really dense and has a lot worth catching.

peter behrens farbenwerk is pretty great, too. i visited in '90 and it was fascinating, a whole 'atrium' of cascading colored bricks. near frankfurt: http://www.greatbuildings.com/buildings/I._G._Farben_Offices.html

i'll second matildenhohe, too. the olbrich work is sublime.

josef kleihues' museum of pre- and early-history - a renovation and addition to a burned church - is a good mid-80s gem.

behnisch's postal museum is near meier's folk art museum.

all frankfurt, of course.