On my way back from Portsmouth, when I am feeling energetic, I take in Portsdown Hill. The downhill is exhilarating (I can go above 40mph!). The uphill route that I take, however, comes up past QA Hospital and it is an absolutely relentless uphill in the lowest or next-to-lowest gear (well, for me anyway!). According to Google maps, It is a climb of 300 vertical feet and is almost exactly 1 mile long, with no slack in the gradient at any point! I call it the "Hill of Death". I should do it more often because there aren't any hills in my regular commute! What is your biggest regular unbroken climb? To qualify it needs to be climbable in low gear only for the entire length (so no climbs with nice little flattish bits in the middle!). EDIT: And no getting off your bike for a rest!