St. Andrews Ringing Society of St. Andrews Cathedral, Honolulu, Hawaii, rang five tower bells half-muffled for the 20th anniversary of September 11th, 2001. They rang Rounds and Call Changes for five minutes, followed by 20 tolling strokes, at the time of each of the four crashes, adjusted for local time in Hawaii. They rang bells 3 through 7--the Dorian five--for a mournful sound. Taking turns ringing were (in alphabetical order) John Paul Brabant, Pam Verrey, Patrick Nguyen, Robert Bley-Vroman, Sasha Bley-Vroman, and Walt Herring.
Photo: A Ocram, public domain, via Wikimedia Commons