A nice looking cobblestone hill in Lewes, UK. I discovered its existence browsing the internet for for reports of steep hills. Par for the course, the author of this query is sure that Keere Street must be one of the steepest, if not the steepest hill in England, suggesting that it must be at least 45-degrees (not even 45%, 45 degrees). Of course, it's not. The cobbles make it a little difficult, and the opening section of 15% is sure to be difficult, but there's a lot of harder hills out there.
Keere Street is located in England. It is 136 meters long with an average gradient of 9.5% and a maximum gradient of 15.8%. Find similar hills.