The main tourist attraction is the Kieler Woche (http://www.kieler-woche.de/) "Kiel Week" at the end of June. See below for more information.
Also famous is in Laboe part of Kiel on the east-side of the fjord the only surviving Type VII-C U-boat from World War 2 at the shore and the "Marine-Ehrenmal" (http://www.museen-sh.de/m...) Navy Memorial with a high tower.
Kiel is famous for the Nord-Ostsee Kanal Kiel Canal, the world's busiest canal. It is possible to walk or cycle for almost the entire length 99km directly along the canal from Kiel to Brunsbüttel estuary of the Elbe, on the North Sea Coast, staying overnight in the town of Rendsburg.
Kiel is the home of the German Baltic fleet, and it is common to see all types of German warships and submarines in the "Förde", including the training sailing vessel Gorch Fock (http://www.gorchfock.de/).
Cultural diversity is offered by the museen am meer (http://www.museen-am-meer...). See below for more information.
kieler woche
Besides being world's largest sailing event the Kieler Woche is one of Germany's largest festivals. Apart from the sailing, the entire center of the town is transformed into an international food and craft fair, with regular big name performers appearing nightly. If you intend to visit Kiel during this time book your hotel well ahead and bear in mind that the waterfront and major parts of downtown will be inaccessible for cars.
Information on events is posted all over town and through a free magazine which will be distributed about a month before the event. Events include entertainment for kids during daytime throughout the entire week and lots of open air concerts. Most concerts end around 11PM and nightlife moves to indoor venues as well as the Eggerstedtstrasse.
Aside from an abundance of food and drink outlets along the streets the International Market on the Rathausmarkt is the place to go for food and drink. A few dozen countries operate booths on the open-air market offering food and drinks from the particular countries. The Kieler Nachrichten newspaper runs a special about food on the market in its Saturday edition. If you cannot decide from the endless choices head over to the Scandinavian area or to wherever crowds are gathering.