Once I climb down from the top of Down Tor itself, I'm expecting to see the first of today's sites. After all, it's a very well-preserved circle, together with a 350m long row and a terminal stone standing nearly 3m tall. In fact, there's no sign of it until I head further east. Suddenly I'm over a small crest and practically on top of this megalithic wonder. What a beauty this is! The circle itself is lovely, 12m across and surrounding the remains of a damaged but recognisable central cairn. Another cairn sits a few yards away to the northwest. This really is a terrific site, aided by the splendid isolation I get here today.

And then there's the row. It extends away to the northeast, heading further into Dartmoor's magnificent empty space. Clouds race past, drawn towards a convergence over the horizon. At the southwestern end, next to but separate from the circle, the row terminates in a huge upright monolith, almost 3m tall and very thick - it weighs about three tons. Seen from this end, the row appears pretty much straight (which it is). It leads uphill towards another cairn, as well as a small prehistoric enclosure. By the time I reach the northeastern terminal stone, the row appears to curve away back to the cairn circle. This is actually an optical illusion, caused by the gently sloping contours that the row crosses. This weird "not curve" further enhances what is undoubtedly one of the best sites I've been to. I still struggle rather with Dartmoor chronology and don't really know whether the row post-dates the large-scale clearances carried out during the Bronze Age. It's hard though to imagine creating such a wonderfully designed monument in the middle of trees, where the form could not be easily appreciated.

To the northeast of the row, but not aligned with it, is Narrator Brookhead enclosure. It's oval in plan and there are no obvious structures (such as hut circles) inside it. The outer wall is still thick, but only a single course high.

At the highest point of the hill, the southern end of the ridge, are two large cairns. The northern cairn is an impressive 20m across. A Bronze Age reave heads WSW down the hill directly from it. But the southern cairn, the Eylesbarrow itself, is bigger still. Another of the reservoir catchment markers stands between the two cairns, on a windswept spot that will be the highest point of my walk today. Without hanging around very long, I follow the reave down the hill.

The ground slopes away to the valley of the nascent River Plym. Between my vantage point and there, an incredible array of monuments and animals is laid out. Cows, sheep and horses fill the space, interspersed with very large upright stones dotted here and there. I've found the rows, at any rate.

But the ground above the "ritual" complex is itself packed with archaeology. Settlement enclosures, round houses and cairns vie for position. One of the first cairns I come across (cairn 15) has some unusual upright stones in its mound, which appear to be in-situ. It's right next to a hut circle. As ever, I don't have the knowledge to really understand the phases of what I'm looking at, which came first and whether the living were sharing their space so closely with the dead. One cairn, much bigger than the rest (cairn 18), is a good spot to view the rest of the site below.

From atop the cairn, the layout of the rows becomes clear, together with their proximity to the even larger Giant's Basin cairn. Three large terminal stones are readily visible, as are three cairn circles in a line at the northeast of the rows. A large herd of cows and another of horses are clustered around the tallest of the terminal stones and other cows and sheep are busy grazing across the site. There are no people to be seen and I get the impression of being an intruder into this primal space.

But the sun is shining and I've travelled a long way to come here, so I'm going to carry on intruding for a while longer yet. The NW of the three cairn circles doesn't have a row of its own, although a low outlier some way to the southwest (which I don't try to find in the bracken today) may indicate an intention that it was to have. This cairn is surrounded by a couple of rings of small slabs, suggesting a complex constructional method.

The central cairn circle has a more obvious outer ring of uprights, and is at the northeastern end of one of the three stone rows that form the complex. The centre of the cairn exhibits the usual central doughnut of excavation. A walk along the row ends in the first (and smallest) of the three enormous terminal stones. This one is a tapering slab, 2.3m high, placed edge on to the row and leaning slightly.

I head towards the southwestern row's terminal stone, but a group of bullocks are getting increasingly lairy around it (once they start trying to shag each other, it's time to back away). So instead I cut across to the Giant's Basin cairn. I do get a good look along the southwest row though, worth noting particularly as it's a double row for part of its length. At its northeastern end is another cairn circle. The slabs at this end of the row have fallen and lie prostrate near the cairn. In addition, there is a small cist between the cairn circle and the Giant's Basin cairn – talk about packed with archaeology! Row 2, well-seen from the Giant's Basin, ends in the largest of the three terminal stones. At over 4m tall, this is the tallest standing stone on Dartmoor. Today, four-legged acolytes, cows and horses, surround it. I don't get too close for fear of upsetting a ceremony of sorts. Its row is the shortest of the three and also ends in a cairn circle, another decent mound surrounded by an incomplete ring of slabs.

I'm awestruck by this amazing place. The primal energies of the animals seem to do it justice and once again I'm filled with the sense that I'm a passer-by, a temporary presence in an ageless space. The bullocks have gradually headed along the southwestern row now, so I skirt their proceedings and make for the now-vacated south-west terminal stone. It's a lovely symmetrical, tapering 3m slab, again facing edge-on to the row.

What a place. I finally leave the complex, heading towards Ditsworthy Warren. I hope to come here again, this is a site to treasure.

There's something quite satisfying about squelching across sodden moors in the pouring rain. Once you've accepted you're going to get wet, there's no shelter and no short-cut, a sense of purpose kicks in. So with this feeling, I reach the northern end of Ringmoor Down stone row. After the wonders of Drizzlecombe, the tiny terminal stone is surprising, but it shares with Drizzlecombe Row 1 a partial double section (which may not actually be authentic here). Taking pictures is difficult, as the lens gets wet every time I point the camera anywhere but downwards. Eventually I get up to the cairn circle, by which time the rain has got even heavier. This is actually a great little cairn circle, with decently spaced uprights (one of which looks rather as if it might be upside down). The central cairn is badly reduced. I could imagine spending a lot longer here, if it weren't so wet. Instead I squelch onwards.

The first of the "proper" Dartmoor circles I've visited, Brisworthy is brilliant, even in the 45 degree rain. It's set on a sloping hillside, and the eye is immediately drawn to Legis Tor across the valley to the east. It reminds me of other circles that have intervisible rocky outcrops nearby – Boskednan/Carn Galva; Tregeseal/Carn Kenidjack; Nine Ladies/Robin Hood's Stride. All of these must have been built to sit as part of the bigger natural landscape, it's an unavoidable connection. The stones of the circle are nicely graded too, and around its outside (particularly on the east) I notice that there are quite a number of small quartz stones in the ground, almost as if there was an outer ring. Be interested to know what anyone else makes of that (if anything!).