What are whispering galleries?

          A whispering gallery is a place where a whisper is audible anywhere or everywhere inside it. Such galleries are made in circular buildings. Their working is based upon successive reflections of sound from its opposite walls. Since there is no loss of energy, the sound of a whisper can be heard at a great distance inside the gallery. For receiving a clear whisper, the ear must be kept close to the wall of the gallery, and it would sound as if the walls are whispering. Hence this name.

          The St. Paul’s Cathedral in London has the most famous whispering gallery. It runs around inside its dome. If you speak inside this gallery the sound waves of your voice would be carried round to the opposite side of the gallery.

          It happens because the waves are successively reflected from the walls and are prevented from going outwards by the stones lining the circular wall.

          The great dome of St. Paul’s has, in reality, two domes — an outer dome with a diameter of 148 feet, and an inner dome whose diameter is 103 feet. The hollow space between the two domes acts as a whispering gallery. There is a whispering gallery in Lucknow Imambara too. Many visitors come to see it.