The Whispering Gallery at the St. Paul’s Cathedral is considered one of London’s most visited accidental man-made attractions. The whispering gallery sits 30 meters (98.5 feet) above the crossing of the nave. It is a circular walkway that hugs the base of the dome structure at St Paul’s. If you whisper something on one end of the wall, another person can hear it at the other end, which is why it is known as Whispering Gallery.