Here are some photos of work going on around Unter den Linden:
Visitors to Berlin are often mystified by what those blue or pink tubes are you see everywhere near building sites. Well, no real mystery. Berlin you see is built on a sandy swamp. The groundwater is very close to the surface, which is why Berlin's U-Bahn stations don't go down very deep. In fact, all of the old buildings in central Berlin - The Dom, the museums, the opera house, the Humbolt University etc - are supported on thick, ancient wood-piles driven down into the swampy soil, just like Venice. Dig a hole anywhere in Berlin and it very soon fills with water, and so the pipes are there to pump the water away. If you follow the length of these blue and pink pipes you will find that they go down to the Spree river or one of the canals to disgorge their watery load.
But why the pastel colours? The pipes have been supplied to Berlin construction firms for decades by the company Pollems GmbH. They consulted a psychologist about what are the colours that children like, and the colours pink and purple were suggested. So there you are!
And here is the song 'Berlin bleibt doch Berlin' itself, composed in 1949 by Will Meisel. I await the Rammstein version :)