Great cities have signature bridges, and this is Philadelphia's. The Benjamin Franklin Bridge, designed by Paul Cret (one of the architects of the parkway across town) was the largest single-span suspension bridge in the world (1 3/4 miles) when it was finished in 1926. The bridge carries cars and commuter trains and also has a foot/bicycle path along its south side, more reachable than ever since Independence Mall has been expanded to the edge of the bridge. For the bicentennial of the U.S. Constitution, a Philadelphia team including Steven Izenour, a leading American architect and planner, created a computer-driven system for illuminating each and every cable. At night, Philadelphians are treated to the largest lighting effects show since Ben Franklin's kite. Walkers and bikers are welcome to cross during daylight hours. Those of us who are slightly lazier can opt to pay $2.05 to see it from the bridge-crossing PATCO train. (Visit for stations and schedules.)