1st.century Roman graves.They resemble 50ft.tall cup cakes.As can be seen in image,one grave has a handrail and wire faced treads to help the intrepid visitor to ascend to the 50ft high summit.
see http://www.megalithic.co.uk/article.php?sid=7394
see http://www.eastspace.net/bartlow/DisplayArticle.asp?ID=5245
see http://news.bbc.co.uk/local/cambridgeshire/hi/people_and_places/history/newsid_8692000/8692856.stm