The Kiel Week or Kiel Regatta is an annual sailing event in Kiel, the capital of Schleswig-Holstein, Germany. It is the largest sailing event in the world, and also one of the largest Volksfeste in Germany, attracting millions of people every year from all over Germany and neighbouring countries.

Kiel Week is held annually in the last week in June, and opens officially on the preceding Saturday with the official Glaser, followed by the Holstenbummel. Kiel Week, ends with a large fireworks display at 11 p.m. on Sunday, fired from pontoons or the quays at the Howaldtswerke, visible all across the Bay of Kiel. 

Kiel Week usually gathers around 5,000 sailors, 2,000 ships, and about three million visitors each year. 

The event is organized in a joint effort by the Yacht Club of Kiel, the Norddeutscher Regattaverein, the Hamburger Sailing Club, and the Verein Seglerhaus am Wannsee.

What once began on 23 July 1882 as a competition between naval officers and merchants with 20 yachts is now regarded as the “mother of all regattas” with 2,000 ships, yachts and boats and around 4,500 sailors.

Most ship races begin at the Olympic Harbor of Schilksee, also the centre of most sporting activities during Kiel Week. As Schilksee is located outside of the inner city and most sailing competitions take place yet further out, only some races – mainly of smaller boat types – can be viewed from shore, namely from along the Kiellinie at the west coast of the Bay of Kiel.

According to en.wikipedia