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
National Portrait Gallery, London In 2012, the Gallery licensed 53,000 low-resolution images under a Creative Commons licence, making them available free of charge for non–commercial use. A further 87,000 high-resolution images are available for academic use under the Gallery's own licence that invites donations in return; previously, the Gallery charged for high-resolution images. , 100,000 images, around a third of the Gallery's collection, had been digitised. National Portrait Gallery, London The National Portrait Gallery (NPG) is an art gallery in London housing a collection of portraits of historically important and famous British people. It was the first portrait gallery in the world when it