Photo of Rundetaarn's spiral ramp in Copenhagen, Denmark

Weekly Gem #32 A good vantage point to see the blue moon ...

Published 8/1/2015

Location:  This 'hidden gem' is located in Copenhagen, Denmark (see Clue Me! Map). As Europe's oldest observatory, we imagine many people wound their way up the clockwise ramp so they could see last night's Blue Moon from the top of the tower. Maybe they even took along a snack of green cheese (which would look much like the blue moon, i.e. big, round, and ... white ). Then unwind on the counterclockwise stroll back down. The tower is laden with interesting history and details, and is clearly worth visiting at least once in a blue moon.

It is also interesting to see how much steeper the climb is close to the center.  Compare the floor along the center wall on the left side of the photo with the outside wall on the right side of the photo. Knowing the slope and the optimal lines to ride in the climb and the descent is undoubtedly a secret to winning the annual unicycle race.


Here's the hidden gem entry from our Clue Me! map.


How steep is it, anyway?


The slope and length of the Rundetaarn's spiral ramp is quite different depending on the line you take.

Why It's Interesting

The inside edge of the ramp is roughly 3 times steeper than the outside edge. This is obvious once you notice that you need to go up about 15 or 20 feet with each turn, and that the circumference (i.e. horizontal distance) at the inside wall is about 1/3 the circumference at the outside wall. So maybe a shorter but steeper exercise going up (stay against the inside wall), and a longer and gentler descent to protect the knees (outside wall).

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