There are a ton of brightly colored pipes winding all around Berlin. At first I thought they were an interesting art installation since I couldn’t imagine why pipes should come out of the ground, twist around completely inefficiently, snake around corners, and then end on a sidewalk or disappear out of view. And the fact that they are pink, purple, and blue was also suspicious.
I still haven’t figured out what the colors indicate, but it turns out that they pipes do serve a very useful purpose. Because Berlin is only very slightly above sea level, pipes are needed to flush water out of construction sites and into a nearby river or lake. And the circuitous paths of the pipes are specifically designed to prevent breakage in very low temperatures. So, because there are countless construction sites…
For more, see this and this.