I finally visited this WHS in April 2015. I say finally because I had been wanting to visit and 'complete' Belgium's WHS since 2012 when the site was closed to build a visitor centre and make it more accessible. The site was planned to reopen as early as 2013 but a series of postponements meant that the new interpretation centre was only inaugurated on Easter Saturday, 4th April 2015. The easter weekend was advertised as Mons' celebration period as European Capital of Culture 2015 and Silex's interpretation centre was only 1 of 5 new museums inaugurated during that weekend with free entrance. Well, I seized the opportunity and visited Mons and Spiennes. By car, Silex's is best reached through Hyon as now there are several signposts indicating the way to the site and there's only a short 10 minute walk on a flat terrain making the site wheelchair accessible. Otherwise the site is reachable through Nouvelles where again there are a series of signposts indicating the way to a dead-end amidst the Belgian countryside and fields. Cars can be parked here and a 12 minute walk on a muddy terrain past a 1915 aqueduct and water management area and a fleet of stairs lead you to the new interpretation centre. I opted for the latter only because I had time to kill and enjoyed some birdwatching along the way. The Silex interpretation centre proper seems quite futuristic and out of place compared to its surroundings yet at least the WHS is much more accessible and the experience is more informative overall. Outside the centre there were several excavations still going on and many archaeologists willing to explain the importance and the OUV of the 6000 year old site in Spiennes. Inside the interpretation centre there are several flintstones and tools displayed, many information boards, a projection room to enjoy a virtual descent into the mine with panoramic photography. To be able to descend the now fully lit Neolithic mine is quite a tall order in bureaucratic terms. However, where there's a will there's a way and by booking ahead from the tourist information office at the Grand Place in Mons I managed to be one of the 12 lucky visitors who got to climb down the extremely safe wide ladder (it's not the black narrow iron one any longer!) with a harness, a helmet, headlamp and IMHO excessive safety gear. The extra ventilation, lighting and safety surely comes with a hefty price tag, now costing 18 euros instead of the cheap 2,50 euro ticket charged until 4 years ago. For WHS enthusiasts, I would say it's a must to visit to get the full unique experience. That said, it really is nothing special (aesthetically) when compared to other WHS mines I visited worldwide. The most interesting geoligical fact I learnt from visiting this site was that raw flintstone is white from the outside and blackish grey inside. However I could have safely learnt that without descending the mine itself. Only a maximum of 5500 people annually are supposed to visit the mine by descending the ladder but I don't think that there will actually be that much of a demand contrary to what is the case with other WHS such as the Lascaux cave, the Chauvet grotto or the Altamira cave. It's worth mentioning that it's not possible to descend on Mondays and it's always better to call the Mons tourist information office to get an English archaeologist/guide and ensure that there are enough visitors on a given day (12 people minimum). The full experience including the descent to the mine will last around 2.5 hours.