The current record holder for loudest crowd in history are the fans of the Seattle Seahawks, who cheered so loud that they induced a mini-earthquake. But that level of noise can permanently damage fans' hearing. Scott Eklund/AP hide caption

itoggle caption Scott Eklund/AP

Musician Jake Orrall performs onstage at the Coachella Valley Music & Arts Festival on April 14. Temporary hearing loss following concerts and other loud events may protect our ears from more permanent damage. Frazer Harrison/Getty Images for Coachella hide caption

itoggle caption Frazer Harrison/Getty Images for Coachella

Composer Richard Einhorn lost most of his hearing several years ago, but that hasn't held him back, thanks to state-of-the-art digital hearing aids. Kevin Rivoli/AP hide caption

itoggle caption Kevin Rivoli/AP

If you know some mice that took This Is Spinal Tap too literally, they might want to know about an experiment to restore hearing with a failed Alzheimer's drug. The Kobal Collection hide caption

itoggle caption The Kobal Collection