Discover Chicago's North and South sides through the windows of the Gray Line bus.. The Scene While contemplating which city tours to recommend for your out-of-town guests, you are left with choices that, for the most part, concentrate on sites in the Loop or near the Magnificent Mile. One exception is the series of Gray Line bus tours, which offer passengers several multiple-hour tours of the city's North and South sides. While the tours give people a feel for the city's layout and introduce some interesting sites outside of downtown, passengers shouldn't expect a thorough or even accurate account of Chicago's architecture, history and institutions. The Skinny The Gray Line drivers, who also serve as tour guides, learn what they know about Chicago from a vague set of guidelines provided by the international company and from their own research. Quality control seems to be very low. Aside from certain factual errors that one perhaps could expect from a bored and over-worked tour guide, drivers are encouraged to emphasize those aspects of Chicago they feel are most interesting.