"In 1912 during the 1912 Summer Olympics the city of Berlin was designated by the International Olympic Committee (IOC) to host the 1916 Summer Olympics. Germany's proposed stadium for this event was to be located in lands located in Charlottenburg, in Grunewald Forest, to the west of Berlin -- thus the stadium was also known as Grunewaldstadion. A horse racing-course already existed there which belonged to the Berliner Rennverein, and even today the old ticket booths survive, on Jesse-Owens-Allee street .) The government of Germany decided to keep the nearby Grunewald forest as it was, as well as the exisiting built environment. With all this in mind they hired the same architect who originally had built the "Rennverein", Otto March."to find out more...
And for the FIFA World Cup 2006's link~
Passage from http://en.wikipedia.org/wiki/Olympic_Stadium,_Berlin
Image from http://www.stadiumguide.com/germany2006.htm