St. George's Chapel, within Windsor Castle, is very impressive. Besides being the site of several royal weddings, funerals and the like, the chapel is the home of the Order of the Garter, and the inside is decorated with the coats of arms of current and former Knights of the Garter. (Sadly, photography wasn't permitted inside.)  
 
 
Image Copyright © 2005 Jessica Thompson Blatz, all rights reserved