Forget Wall Street, Park Avenue and Broadway. Tunnel Approach and Tunnel Exit Streets, perhaps the most heavily traveled thoroughfares in the city, remain the least visited.Only a few blocks from Grand Central Station, Bryant Park and the United Nations, to say nothing of the Midtown Tunnel, these aptly named streets give access to the city for some 70,000 cars per day.  It is true the Tunnel Street sidewalks are narrow.However there is an abundance of artwork Plenty of street foodEven a few wildlife specimens. One only has to look beyond changing lanes to see.