Definitely stroll along the beautiful Alster and enjoy the stunning surroundings whilst in Hamburg. I imagine this river even more beautiful when the sun is out, but it was still lovely in the middle of winter. This is the second river in Hamburg, the other one being the Elbe, and it's in the centre of the city. It's lovely to walk around here, and see all the locals jogging and people out walking their dogs. There are also many cafes and restaurants around to stop in for a quick refreshment.