The world's steepest street.

Baldwin Street in Dunedin. Apparently they planned these city streets from an office in London, and the map they used didn't have any contour lines on it.

This little nugget of hillclimbing goodness rises 70m (210ft) along its 350m (1150ft) length. Thusly, it sports an average gradient of 20%, but maxes out at 35%. Obviously, I had to try and ride it. I stopped a third of the way up to shed some bags off the bike, and heaved my way up. I nearly lost my lungs doing it and my throat still hurts. Brilliant fun!