1859
French acrobat Charles Blondin was the first person to walk across Niagra Falls on tightrope on June 30, 1859.
Source: The Advertiser (AU), 6/30/2006

"Ringling Bros. United Monster Shows, Great Double Circus, Royal European Menagerie, Museum, Caravan and Congress of Trained Animals"
On May 19, 1884, the seven Ringling brothers -- Al, Gus, Otto, Alf, Charles, John and Henry -- put on their first performance in Baraboo, Wis. During their first performance, the circus tent collapsed onto the bleachers.
Source: Washington Times, 4/1/2004

Ring

Source: Newsday, 2/5/2006