Events & Activities What's On/Events Bourn Windmill Open Day Sun 13 September, 2pm-4pm Bourn Windmill Open Day Bourn windmill is one of the oldest in the country, set in beautiful scenery. The mill will be opened and guides will show you how the mill works and tell you the history of this fascinating building. Not only can you see inside, you can also have a go at the incredible task of turning the whole mill on its post - an amazing experience. The mill is owned by local charity CambridgePPF and run by dedicated volunteers. Tea and cakes available to purchase. Members free, non-members £3 adult, £1 per child. No need to book.