Congress Of Vienna was an international conference that was held in efforts of reestablishment of Europe after fall of Napoleon. It was attended by the ambassadors of all the major powers of Europe and was chaired by Austrain Statesman Clemens Wenzel. It was held in the city of Vienna from November 1, 1814 to June 8, 1815. The aim of the conference was to determine the shape of Europe after Napoleonic wars. Several geographic changes occured in Europe after this conference. You can have complete details at the link below:
en.wikipedia.org
en.wikipedia.org