Today, I was in St. Louis with a group from a writing conference, and we had lunch at union station. While there, someone showed us a cool feature in the architecture called the whispering arch. This very ornate arch is built over the doorway to the grand hall. The way the architecture turned out, the arch creates the perfect avenue for sound waves to travel. If you stand facing the wall, you can speak very softly, and someone standing on the opposite end of the arch can hear you perfectly. It is so cool. While we were experiementing, people kept walking by, looking at us like we had really lost it. So, we showed them too. Here's a so-so link to the place.