The Devil's Kneading Trough, part of the Wye Downs in Kent, as the name suggests is an absolute killer of a Strava segment.
The top of the hill is a massive 152 meters from ground level, but (lucky?) the start of the segment is around the 70-meter mark. When you come through the trees about a third of the way is when the incline really hits you. It's one for the cross country pro or the trail runner lovers.