. . "1798" . . "Hilfield Castle, also Hilfield Lodge, is a country estate and house about 1.8 miles (2.9 km) by road southwest of Aldenham, Hertfordshire, on the outskirts of London. It contains a large reservoir which was built by French prisoners of war in the 1790s, and Elstree Aerodrome is located just to the east and the M1 motorway passes to the west."@en . "1799" . . . . "Hilfield Castle"@en . .