Stonehenge is difficult to understand upon merely a casual visit.
To grasp the unique character of this, the oldest prehistoric monument
in Europe, and perhaps in the world, we must take for granted the
investigations and discoveries of antiquaries and archaeologists
during the last 250 years, and if the comparison between their
conjectural but approximately correct plans and the present aspect of
this mysterious relic of the Stone Age is disappointing and
perplexing, we can only be thankful that the work of Farmer Green and
Tom Robinson, the two despoilers mentioned by the earliest
investigators, has been prevented in their descendants, and that
though the circles are incapable of restoration, the few stones that
remain will be preserved for all time.

Avebury is undoubtedly older than Stonehenge and must belong to the
true Neolithic period, whether the former does or not. Of the original
six hundred and fifty megaliths eighteen are standing and about the
same number are buried. Some are nearly 17 feet high, and the rampart
that encloses the Temple is no less than 4,500 feet round and from 10
to 20 feet in height, though it is computed that from the bottom of
the ditch to the wall must have originally been nearly 50 feet. The
modern village, built of some of the missing stones, is partly within
the circular earthwork. This rampart is the only part of the great
work which can be readily comprehended by the visitor. A circle of one
hundred stones is said by the archaeologist Stukely to have stood
around the edge of the enclosure, forty-four still standing in his
time (1720). The same writer asserts that within the great circle were
two other separate rings consisting of thirty stones, and each
containing an inner circle of twelve stones. The northern of these
rings had three large stones in the middle; the southern, one enormous
stone 27 feet high and nearly 9 feet round. One, or possibly two,
avenues of stones led south-east and south-west; that going in the
direction of West Kennet may still be traced and fifteen stones
remain, but the other is conjectural, if it existed at all. The two
megaliths seen from the Beckhampton road may be a remnant of it. The
purpose of all this intricate and elaborate work is a puzzling problem
and, like the mystery of Stonehenge, will probably remain a secret to
the end. The literature of Avebury, not quite so copious as that of
the stones of the Plain, is also more diffident in its guess