Just got back from Crackow, Poland, where they are restoring a Kopiec. It's an artificial hill 34m high - and sits on the small plateau of one of the city's hills.
It has the same dimesions as Silbury, but looks so huge when you get up close.
Like Silbury, it's damaged; water mostly, so its undergoing a substantial restoration.
It was built in 1820-23, so quite recent, and therefore some record of how it was built exists.