The 9/9bis Sensitive Natural Areas has a past closely linked to mining. This was the last mine to be closed in the region, on 21 December 1990. Since then, this 158-hectare site has been taken over by nature and presents a wide variety of environments. The slag heap, woodlands, lawns and ponds now host an exceptional biodiversity. The Les Hautois Woods has been classified as a Sensitive Natural Area since 1983. It was on this site that coal was discovered for the first time in Pas-de-Calais, by an engineer named Ms Declercq in 1842. In addition to this exceptional historical heritage, the Les Hautois Woods offers a pleasant walk in a preserved setting where fauna and fauna thrive.