Hmmmm...

When the French team surveyed the Great Pyramid, they used microgravimetry, a technique that enabled them to measure the density of different sections of the pyramid, thus detecting hidden chambers. The French team concluded that there were no large hidden chambers inside it. If there was a ramp inside the pyramid, shouldn't the French have detected it? In 2000, Henri Houdin was presenting this theory at a scientific conference where one of the members of the 1986 French team was present. He mentioned to Houdin that their computer analysis of the pyramid did yield one curious image, something they couldn't interpret and therefore ignored. That image showed exactly what Jean-Pierre Houdin's theory had predicted--a ramp spiraling up through the pyramid.
http://www.archaeology.org/0705/etc/pyramid.html




Silbury Hill and West Kennet Long Barrow by Moira Allen

Originally the mound was thought to have been built in concentric layers, like a cake (hence the terraces). Another view, however, is that it was actually built in a spiraling pattern, rising from the bottom to the top. Again, experts disagree on why this might have been the case. Some believe that the spiral indicates a ritual processional path to the top of the mound; others believe that this was simply a much easier method of construction than the layer-cake approach. Given that the terraces of the mound were apparently smoothed over as part of the original construction process, and not at some later time, the second theory seems more likely; if the spiral had been intended as a road, one would imagine that it would have remained in use for a period of time before being covered over. In fact, the mound does not appear to have been designed to have been "climbed" at all; its smooth walls do not permit one to simply walk up to the top, without carving a new pathway (which, based on drawings of the site by William Stukeley in his 18th-century book Abury - A Temple of the British Druids, appears to have been done in later times). Quite possibly, therefore, the mound was not built to be used, so much as to be observed from another location.




http://www.timetravel-britain.com/articles/stones/silbury.shtml