Visit the lobby of 224 S. Michigan Ave., now through May 2, to see the new exhibit which answers the question, "What should a park look like in the 21st Century?" The exhibit drew more than 100 entries from around the country, and 30 select designs are on display in the lobby of the 100-year old office building designed by Burnham's firm and housed his offices. The show asked architects to create new visions of outdoor public space by fleshing out Mayor Richard M. Daley's idea to extend Lincoln Park northward 2 1/2 miles to the Evanston border.