Six kilometres southeast of Mons, a peaceful agricultural scene covers what was a major Neolithic flint-mining site. One of the most impressive shafts is covered by a small modern museum, which gives decent information on how the flint was knapped and made into durable tools. Three daily 90-minute visits descend to the mine – an atmospheric experience – but must be prebooked well in advance (around 15 days' notice) via Mons' tourist office (firstname.lastname@example.org). Children under age 10 aren't allowed in the mine.
There's access for travellers with disabilities, but otherwise you must park 1km away and stroll through pleasant farmland. There are buses to Spiennes from Mons.