My wife and I spent a long weekend in Hamburg. A couple of friends from Hannover joined us and it was good fun. What I liked in particular about Hamburg is its mix of modern buildings and old brickwork constructions. And the water. It's river and canals everywhere. A great place to visit. The city has the third largest harbor of Europe. Pro tip: book a visit of the harbor with a bus. The tour is given in German only, but you will have the unique chance of entering the container harbor and watch the gigantic cranes load a super container ship. Impressive.
The city is bustling with construction works, as it is expanding rapidly. The so-called Hafen-City expansion is about to double the surface of the city centre. Remarkable.
The old parts of the city are quite charming. Despite the rain, I liked our walk in the Speicherstadt, which (back in the days) used to host the warehouses for the goods offloaded from the ships.
The nightlife revolves around the Reeperbahn, the read-light district (hey, pretty normal, it's a harbor city!) which now also hosts many bars and clubs. It's also a popular place to go to with your friends to celebrate your bachelor/bachelorette party.
The Elbe river is the star of the city. The best view is from the bell tower of the Michel (= St. Michaelis church).
But to get up-close, you should catch one of the ferries that go from Landungsbrücken all the way up to the Elbstrand and back. Bring a Wegbier (a beer "for the road"), sit on the deck and enjoy the views.
And of course, the tour of the city must include a visit of the Elbphilharmonie. It's construction stirred the waters quite a lot in the German public opinion, as the building took forever to build and the costs went through the roof. After the Berlin airport, this is the other topic Germans don't like to talk about :) The view I liked the most was from across the river, from the platform in front of the "König der Löwen" theatre (yes, they built a theatre that has been playing the Lion King... exclusively... non-stop... for the past 10 years! Must be the equivalent of "Cats", for Germans). Anyway, thank you Use for the ride over there and the private tour.