http://www.post-gazette.com/stories/...-dozen-663572/

Wow, and I thought that 20% was painful. Of course that is a
mile long. but 37% is amazing. You can't pave something that
steep so it much be built of stones.

=v= Many Pittsburgh streets are brick, with cobblestone for the
especially steep sections.

=v= I grew up biking these streets, and have long been puzzled
by people saying that San Francisco is a hilly place to ride. :^)
_Jym_