No doubt others on the list will provide you with a list of fascinating and
rewarding exhibitions, but I trust the (considerable) US contingent on this
list will allow me onen suggestion. The photographic archives of the Art
Institute of Chicago are well worth a visit (preferably one lasting several
weeks!). They have an extensive collection, and some wonderful famous and
rare work by both famous and unknown photograohers. I suspect you need to
set up an appointment in advance, but it is DEFINITELY worth the effort.
Bon Voyage!
Jonathan Anderson