Avebury & Silbury Hill - Day Trip
Although Stonehenge was started before Avebury, it was a major earthworks with a bank. Some 500 years 
before stones were transported to Stonehenge, they were collected and erected at Avebury. The first phase began around 2,600 BC and involved erecting an enormous henge - huge ditches with the spoil piled into banks. These were dug using antlers and cattle shoulder bones. Once this back-breaking phase was complete, stones were selected from the nearby Marlborough Downs.
Some, such as the Swindon Stone weigh fifty tons. Huge teams would have been needed to attach the leather straps and 'rollers' created from rounded logs. In addition and something which is little mentioned is the cost of the effort. In early farming communities, it was and is essential to obtain food at a lower cost to the energy expended in getting it. The amount of sustained effort required to build these monuments would have taken vital workers away from agricultural efforts and put them into calorie-sapping, never-ending heavy lifting and hauling. It's this aspect of their construction which interests me most. Their will and desire to create enormous monuments (like the nearby long barrow at West Kennet, and the jaw-dropping Silbury Hill) is difficult to comprehend when you consider that they were boring into chalk with antlers and bones. It would take hours of effort to make a small indentation and none of it was putting food on the table. I understand that farming improvements and the introduction of pottery and food storage techniques allowed greater freedoms, but these were brave and risky undertakings.
Once the stone was selected and assigned a place in the circle (there was 400 stones in the circle and great avenues). A small hole was excavated in the chalk and the stone was manoeuvred into place. Stakes were set into the 
nearby chalk and the stone was heaved into place. Great care was taken to balance its centre of gravity, over the hole it was positioned into. Although the holes are shallow, stones such as the Swindon Stone have balanced for over 4,500 years precariously on one corner, with only a small fraction of it underground. Packing material and chalk blocks were used to keep it in place initially, but these have been weathered back, leaving the stones to perch jauntily above the ground.
Silbury Hill
Silbury Hill is very close to Avebury (you can see it from the National Trust car parks, if you come by road) and like the West Kennet Long Barrow, was built by the same indigenous people. It has remained uneroded for 4,500 years and was built using the same tools as the the Avebury henge (antlers and animal shoulder blades).
Silbury Hill is 130 feet high and covers over 5 acres, making it the largest man-made ancient mound in Europe. It is built as a series of drums, one on top of the other getting progressively smaller as you near the summit. Inside each drum are a series of walls which were first thought to be circular and filled with chalk. It's now understood that they are polygons rather than circles, which raises the question of where such ancient people learnt advanced techniques in engineering stability.
Recent excavation has also indicated there are Sarsen stones within the mound and that the mound conceals a megalithic structure. Also, very recent carbon-dating has adjusted its building to a century after the Avebury ring, instead of before it, as was previously thought. This means that existing theories as to the purpose of the entire site, must be re-assessed.
If you're planning a visit to Stonehenge, then allow more time for Avebury, Silbury Hill and the West Kennet Long Barrow. 
They really are one of the UK's most enduring and magical sights. The Michael and Mary ley lines run through the site and it's also common for electrical gadgets to fail inside the circle (phones, sat-nav and similar - and likely due to the magnetic properties of the stones). The Swindon Stone is reputed to swivel on its access and occasionally to cross from one side of the road to the other at midnight (not convinced about that). There are so many ghost stories, that every house in the village claims to have one.
What is undeniable, is that the village possesses an intense energy - similar to the buildup of tension before a thunderstorm. It's unusual and I've yet to meet a disappointed Avebury visitor.
Slideshow streamed from YouTube of common sights around the village of Avebury, from a recent visitor.
"Children of the Stones" - TV programme from the '70s which introduced me to the Avebury Ring. Elements of it appeared in the movie - "Hot Fuzz".
For further information about Avebury and surrounding historical sites - take a look here.
Avebury is a UNESCO World Heritage Site.
Avebury Village and henge, Wiltshire.
