In June 22, 2020, the discovery of the largest prehistoric site ever found in Britain was announced, consisting of a large circular ring of shafts surrounding Durrington Walls henge monument. I recognised at a glance that there was a clear geometrical relationship based on the heptagon between the two landscape forms.

When I heard this news, I happened to have been rereading Anne Macauley’s Megalithic Measures and Rhythms: Sacred Knowledge of the Ancient Britons (2006). The author shows how the dimensions of stone circles were determined by regular polygons laid out in Megalithic Yards. In particular, I had been studying several examples of circles she describes governed by a seven-pointed, or heptagonal geometry. When I first saw the map of the newly discovered circle of shafts around the henge of Durrington Walls, I immediately recognised the same proportions, and wondered if it too was laid out using seven-pointed geometry.

“A circle of deep shafts has been discovered near the world heritage site of Stonehenge, to the astonishment of archaeologists, who have described it as the largest prehistoric structure ever found in Britain. Four thousand five hundred years ago, the Neolithic peoples who constructed Stonehenge, a masterpiece of engineering, also dug a series of shafts aligned to form a circle spanning 1.2 miles (2km) in diameter. The structure appears to have been a boundary guiding people to a sacred area because Durrington Walls, one of Britain’s largest henge monuments, is located precisely at its centre. The site is 1.9 miles north-east of Stonehenge on Salisbury Plain, near Amesbury, Wiltshire.”

**Slides 2**

Anne Macauley’s Megalithic Measures and Rhythms: Sacred Knowledge of the Ancient Britons (Floris Books, 2006) showing heptagonal geometry in stone circles, including Stonehenge.

She shows how the ancient builders of the stone circles employed a right-angled triangle with sides of ratio 51:22:46 for generating the 360/7° angle.

**Slide 3**

The image shows the result of adding a best fit circle to the postholes, and completing a seven-pointed star, or heptagram, aligned north-south.

Notice that four of the seven points coincide with postholes falling on the best fit circle.

Durrington Walls earthworks occupies very exactly the central region of the heptagram.

The diameter of the outer circle is 2,700 MY, or 2,700 x 2.72 = 7,344 feet.

These are the triangle marked in red in the diagram is a [51:22:46] Pythagorean triangle.

It is laid out in units of 144 feet.

The three sides have lengths of

144 x 51 = 7,344 feet,

22 x 144 = 3,168 feet

46 x 144 = 6,624 feet.

The short side is interesting: 3,168 feet is 6/10 of a mile.

The mean circumference of the Stonehenge sarsen circle is 316.80 feet, according to John Michell, a number which connects it to the dimensions of the New Jerusalem.

It is also noteworthy that the total perimeter of the red triangle measures 6,300 MY.

The perimeter is 51 + 22 + 46 = 119 units in length total.

The units are 144 feet, therefore the total in MY is: 119 x 144 / 2.72 = 6,300

**Slide 4**

One of the sides of the heptagram points directly to Stonehenge to the south-west.

This implies that the red triangle as depicted in Slide 4 is also a 51:22:46 right-angled triangle.

Very remarkably, the dimensions of the sides of this red triangle are 5,100 MY, 2,200MY and 4,600MY.

Hence, the position of Stonehenge is related to Durrington Walls by a 51:22:46 triangle laid out in units of 100MY.

**Slide 5**

Stonehenge itself contains heptagram geometry, based on the 7 x 8 = 56 Aubrey stones of the outer circle.

The alignment from the Durrington Walls heptagram continues along one of the sides of the Stonehenge heptagram geometry.

The exact corner of the 51:22:46 falls as shown, where the heptagram alignments meet on the perimeter of the Stonehenge outer circle.

(Note Stonehenge nominal heptagram geometry as shown has been rotated to align north south.)

**Slide 6**

The presence of the 51:22:46 triangle in turn implies a circle of diameter 5,100 MY and its inscribed heptagram.

Hence, we have three interlocked circles with inscribed heptagrams, of respective diameters 104 MY (Stonehenge stone circle), 2,700 MY (Durrington Walls) and 5,100 MY (Largest circle).

These fall very near to the expansion ration 1:26:49.

(104 x 26 = 2,704; 104 x 49 = 5,096)

**Slide 7**

The two heptagrams inscribed on the two large circles (“Stonehenge” and “Durrington Walls”) interact as shown.

The outer points of the two hexagrams exactly co-incide, as shown at upper right.

Theoretically, the centre of the large circle and the corresponding point of the smaller of the two heptagrams should also co-incide for a geometrically perfect integration. As the larger circle has a diameter of 5,100 MY, by calculation from the geometry, the Durrington Walls circle if it conformed as above would have a diameter of 2,630MY

In practice, the Durrington Walls heptagram has been constructed at a slightly larger size, in order to create the whole number diameter of 2,700MY and related measures. As a result, the centre of the Stonehenge circle and corresponding point of the Durrington Walls heptagram do not fall co-incident, but are slightly displaced.

**Notes:**

Further observations on the diameter of 2,700 MY.

This can also be expressed as 1,080 Megalithic Rods.

It therefore represents the moon at a scale of 1MR = 1mile.

Ancient Indian writings describe a circle of this diameter 1,080 and associate it with a corresponding circumference of 3,398.

This pair gives a value of pi of 3,398/1080 = 3.14166+

The sexagisemal value of 3,398/1,080 is 3:8,30, a value cited in the Almagest. (see The Exact Sciences in Antiquity, Neugebauer).