Generally speaking, the monuments that represent cities can be categorized as masculine phallic symbols. A quick list: Paris/Eiffel Tower, Seattle/Space Needle, Washington DC/Washington Monument, London/Tower of London, etc.
This is by and large true with one very unique exception: St. Louis. St. Louis is the only city that I know of that is represented by a monument that is a feminine sexual symbol: an Arch. The conceit also underlies the famous slogan: St. Louis, Gateway to the West.
HT: Dr. Barb Osburg
Edit: Here is the Liberty Memorial in KC, courtesy Sam Burnett.
Ducks and Economics 
agreed. Though the historic water-tower standpipe at the Grand Reservoir (hwy 44 and Grand) in St. Louis is perhaps the MOST phallic historical building in the Americas.