The Binnenalster is the part of the river Alster that flows right through Jungfernstieg. It's surrounded by shops, cafés and walking paths, just a few steps away from Hamburg's main shopping area and the central station. For people working in the area, the stairs around the water as well as the little park have become a popular lunch spot.
Whenever you need a break from your shopping frenzy, taking a walk around the 'lake' or sitting down for lunch in the little park just under the bridge will recharge your batteries. There are plenty of viewpoints with the whole Jungfernstieg area laid out in front of you, especially beautiful during Christmas time when it's decorated with lights.
Take a nightly walk up the right side of the Alster from Jungfernstieg to the old bridge. The scenery between the old streetlights is fit for a movie.