The former chapel at the south side of Buckingham Palace is now a temple for Her Majesty's collection of art, comprised of acquisitions made by the monarchy over the years. A splendid portico (designed by John Simpson) sets the scene for spacious galleries whose walls are hung with some of the greatest works in the country. The Pennethorne Gallery is dominated by the larger-than-life portrait by Van Dyck of Charles I, in magisterial equestrian mode, presiding over works by other masters such as Holbein, Hals, Vermeer and Rubens. These contrast starkly with the very frank (and some might say unflattering) portrait of the present queen Elizabeth by Lucian Freud in the Nash Gallery. Also in the galleries are some of the Queen's decorative art objects, including cabinets, tables with precious inlays, vases, silver, as well as the finest porcelain from Delft and Sèvres.The E-gallery provides an interactive electronic version of the Royal Treasures catalog and reveals hidden details of some of the works of art on show, allowing the user to open lockets, remove a sword from its scabbard, or take apart the tulip vases. It's probably the closest you could get to eyeing practically every diamond in the sovereign's glittering diadem. COST: £7.50. Tube: Victoria or St. James's Park.