In Zonta v. Village of Bensenville, plaintiff was injured when he leaned upon defendant's window, which subsequently shattered and caused injury. (167 Ill. App. 3d at 356) The appellate court of Illinois in upholding the trial court's granting of summary judgment in favor of defendant stated that plaintiff offered no hint as to what defect in the glass caused his injury other than his speculation that the glass might have been too thin. The court cited the holdings in Monaghan and Vance in pointing out that liability cannot be predicated on surmise or conjecture as to the cause of liability, but rather plaintiff must establish a prima facie case that some specific defect in the glass must be shown to have been the cause of plaintiff's injury; otherwise summary judgment is proper. (167 Ill. App. 3d at 360).