Whispering gallery to the walls, an effect that was discovered in the whispering gallery of St Paul's Cathedral in London. The extent to which the sound travels at St Paul's can also be judged by clapping in the gallery, which produces four echoes. Other historical examples are the Gol Gumbaz mausoleum in Bijapur and the Echo Wall of the Temple of Heaven in Beijing. A hemispherical enclosure will also guide whispering gallery waves. The waves carry the words so that others will be able to hear them from the opposite side of the gallery. The gallery may also be in the form
St Paul's Cathedral intense piety. In March 2010, Flare II, a sculpture by Antony Gormley, was installed in the Geometric Staircase. In 2007, the Dean and Chapter commissioned Martin Firrell to create a major public artwork to mark the 300th anniversary of the topping-out of Wren's building. The Question Mark Inside consisted of digital text projections to the cathedral dome, West Front and inside onto the Whispering Gallery. The text was based on blog contributions by the general public as well as interviews conducted by the artist and on the artist's own views. The project presented a stream of possible answers to the