I have 'visited' this place twice, in 2001 and 2002.
As you say, it does not seem to exist, at least it is impossible to find. When you reach the village Spiennes, the site is clearly marked with signs 'Sites prehistoire de Spiennes', but when you have gone through the village, all traces disappear. There is no way to find out where to go. I went to the tourist office in Mons, and they had a brochure saying that the site is closed until further notice, because of the dangerous condition of the site.
But why do they insist on having the signs along the streets???
Of my 230 sites, this has been the most disappointing.
