Dallas has a nice arts district with some very interesting architecture. Dallas Museum of Art is good, but not great. But the building, by Edward Larabee Branes, is very, very nice. The Nasher Sculpture Garden (next door) is very good with a world class building designed by Renzo Piano. (Probably one of the two best buildings in Dallas Ft. Worth, along with Louis Kahn's Kimble Art Museum in Ft. Worth.) Just spectacular.
You can also walk down two blocks and see I.M. Pei's symphony hall, Sir Norman Foster's Opera House, and Rem Koolhaus' new theater building.