5m. On the Upper Tier. Find the archway just right of The Great Hall. On the outer left-hand side of said archway a series of three slopers can be found (see pictures). Standing on the lowest sloper and holding the middle one, dyno to the highest.
Top out if you are brave, dyno to the top if you're braver. Don't get hurt. (there is a right hand variant on the right of the arch).