E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The largest artificial mound in Europe is Silbury Hill, near Avebury (Wiltshire). It covers 5 acres, 34 perches, and measures at the base 2,027 feet; its diameter at top is 120 feet; its slope is 316 feet; perpendicular height, 107 feet; and it is altogether one of the most stupendous monuments of human labour in the world.
Alyattes, in Asia Minor, described by Herodotus, is somewhat larger than Silbury Hill.