The official dedication of the World's Columbian Exposition took place on October 20th, 21st and 22nd, 1892, with the biggest events taking place on October 20th and 21st.
On October 20, a large parade (said to be one of the largest ever staged in the United States to that time) was held on the streets of Chicago. The parade included civic societies/organizations and military units. In attendance was Levi Parsons Morton, Vice President of the United States (under Benjamin Harrison). Parsons observed the parade from the reviewing stand at the US Government Building on the Exposition grounds. The parade was reported as approximately 10 miles in length, and transpired without major incident or injury.
Military Unit in Dedication Parade - Chicago - October 20, 1892
(Image Credit: Library of Congress, Prints and Photographs Division. Public Domain.)On October 21, 1892, dedication ceremonies moved to the Manufactures and Liberal Arts Building on the Exposition Grounds at Jackson Park. The ceremonies included an opening prayer, various speeches, musical performances, presentations, a closing benediction and a national salute.
Manufactures and Liberal Arts Building on the Exposition Grounds
(Image Credit: The Book of the Fair: An historical and descriptive presentation of the world's science, art, and industry, as viewed through the Columbian Exposition at Chicago in 1893. Hubert Howe Bancroft. 1894. Public Domain.)October 22, 1892 saw the individual dedication of the various State buildings of the Exposition.
Note: Though the Exposition was dedicated in October 1892, it was not open to the public until May 1, 1893.The Directors of the World's Columbian Exposition Company had hoped that they would be able to launch the sale of their souvenir half dollar during the dedication events, but the ongoing arguments and controversy over which portrait of Christopher Columbus should be used as the reference for the coin, prevented the US Mint from making coinage dies and striking the coins in time. The first coins were struck about a month after the Dedication, on November 19, 1892. These initial strikes were dated "1892", with later strikes bearing the "1893" date.
So, an ideal opportunity to sell its fundraising coin to a significant number of the many thousands who attended the parade and/or various dedication ceremonies was lost to the Exposition Company. Had the coins been available, I would suggest that far fewer of the program's coins (1892-93) would have been available for release into general circulation and a different picture of the coin's financial success would have been painted. (Another example of how extended arguments over a topic can have a negative impact.)
1892 World's Columbian Exposition - Columbus Half Dollar

For more of my stories about commemorative coins and medals, including other Columbian Exposition topics, see:
Commems Collection.