Mention the circus and a string of imagery comes to mind immediately. Tightrope walkers, freak shows, lions, elephants and cotton candy have been synonymous with the Ringling Brothers and Barnum and Bailey since the early 19th century. The "Greatest Show on Earth" comes to the Tucson Convention Center, 260 S. Church Ave.., Thursday, June 18 to Sunday, June 21 with a new tour, Circus Xtreme. The show will have the classic staples along with new, "xtreme" stunts and never before seen performances. The first showing is on Thursday at 7 p.m. Ticket prices range from $20 to $65 and can be purchased at Ticketmaster. For a complete schedule of showings and to purchase tickets, visit tucsonconventioncenter.com.