A whispering gallery is usually constructed in the form of an ellipsoid, with an accessible point at each focus. When a visitor stands at one focus and whispers, the line of sound emanating from this focus reflects directly to the dish/focus at the other end of the room, and to the other person. Circular whispering galleries may provide "communication" from any part on the circumference to the diametrically-opposite point on the circumference.

Examples

• The Gol Gumbaz in Bijapur, Karnataka State, India.
• Selimiye Mosque in Edirne, Turkey.
• The Echo Wall in the Temple of Heaven in Beijing, China.
• The Fazer cafeteria in Helsinki.
• The Church of the Holy Sepulcher in Jerusalem.
• Statuary Hall in the United States Capitol is a famous example of a whispering gallery.
• St. Peter's Basilica in the Vatican City.
• Santa Maria del Fiore, Florence Cathedral, in Florence, Italy.
• St Paul's Cathedral in London.
• Cathedral of Brasília in Brazil.
• Cincinnati Museum Center at Union Terminal.
• The Mapparium in the Christian Science complex in Boston allows visitors to enter the interior of reflecting surface forming nearly complete sphere, with very striking effects.
• Grand Central Station in New York City the gallery in front of the Oyster Bar restaurant.
• The rotundas of the Texas State Capitol and the Missouri State Capitol.
• Martello towers
• The library of Dollar Academy in Scotland

Whispering galleries also occur naturally in the ocean. Instead of the reflecting surface it is the sound rays that are curved and the reflecting 'wall' (the sea surface) is flat. The same phenomenon occurs for radio waves propagating in the atmosphere.

Caltech in the US has been doing research on optical whispering galleries, which so far are no bigger than 40 micrometres in diameter, and must be filtered to be seen.

See also

• St Paul's Cathedral
• Underwater acoustics
• Sofar channel

References