Four generations of the Marquesses of Hertford and Sir Richard Wallace filled the Hertford House on Manchester Square with the largest and finest collection of art ever assembled by one family. From paintings to swords to armor this mansion is chock full of stuff. I did not spend long here but saw fascinating things (like 3-D sculptural paintings from the 18th century) hung salon style. This collection has fascinated Brits since it was started by the mistress of George IV.