<P> By 1847, the couple had found the palace too small for court life and their growing family, and consequently the new wing, designed by Edward Blore, was built by Thomas Cubitt, enclosing the central quadrangle . The large East Front, facing The Mall, is today the "public face" of Buckingham Palace, and contains the balcony from which the royal family acknowledge the crowds on momentous occasions and after the annual Trooping the Colour . The ballroom wing and a further suite of state rooms were also built in this period, designed by Nash's student Sir James Pennethorne . </P> <P> Before Prince Albert's death, the palace was frequently the scene of musical entertainments, and the greatest contemporary musicians entertained at Buckingham Palace . The composer Felix Mendelssohn is known to have played there on three occasions . Johann Strauss II and his orchestra played there when in England . Strauss's "Alice Polka" was first performed at the palace in 1849 in honour of the queen's daughter, Princess Alice . Under Victoria, Buckingham Palace was frequently the scene of lavish costume balls, in addition to the usual royal ceremonies, investitures and presentations . </P> <P> Widowed in 1861, the grief - stricken Queen withdrew from public life and left Buckingham Palace to live at Windsor Castle, Balmoral Castle and Osborne House . For many years the palace was seldom used, even neglected . In 1864, a note was found pinned to the fence of Buckingham Palace, saying: "These commanding premises to be let or sold, in consequence of the late occupant's declining business ." Eventually, public opinion persuaded the Queen to return to London, though even then she preferred to live elsewhere whenever possible . Court functions were still held at Windsor Castle, presided over by the sombre Queen habitually dressed in mourning black, while Buckingham Palace remained shuttered for most of the year . </P> <P> The palace measures 108 metres (354 ft) by 120 metres (390 ft), is 24 metres (79 ft) high and contains over 77,000 m (830,000 sq ft) of floorspace . The floor area is smaller than the Royal Palace of Madrid, the Papal Palace and Quirinal Palace in Rome, the Louvre in Paris, the Hofburg Palace in Vienna, and the Forbidden City . There are 775 rooms, including 19 state rooms, 52 principal bedrooms, 188 staff bedrooms, 92 offices, and 78 bathrooms . The palace also has its own post office, cinema, swimming pool, doctor's surgery, and jeweller's workshop . </P>

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