More than 100 historic windmills and watermills will open their doors this weekend for visitors to explore the heritage of Britain’s mills.

The attractions, many of which are usually closed to the public, are opening as part of National Mills Weekend.

Since 2010, the Wind and Watermills Society for the Protection of Ancient Buildings has been turning the public’s attention to the importance of restoring and protecting traditional mills.

While the need for mills became obsolete in the early 20th century thanks to the introduction of affordable electricity, there was a time when windmills and watermills were essential to England’s agricultural and manufacturing industries.

By 1870, two-thirds of the power used by Britain for grain milling came from watermills and there were more than 20,000 watermills in the nation. The mills were used for a range of purposes, including grinding bones for fertiliser, paper manufacturing and powering forge hammers.

The annual celebration of the country’s mills and the people who care for them will see three fascinating venues in Kent taking part on Saturday, May 11 and Sunday, May 11.

WHITE MILL, Sandwich

While this windmill in Sandwich has retained much of its original wooden machinery, dating back to around 1760, it is currently undergoing renovations to return it to working order. Over the weekend, visitors will be able to see the progress made so far and find out what the future holds for the mill from the on-site volunteers. The mill’s Rural Heritage Museum and gardens will also be open and the barn will be filled with craft stalls, food stalls and family entertainment.

Details: Open 10am to 4pm. Entry is free.

UNION MILL, Cranbrook

After being taken over by a union of local farmers and businesses in the 1800s, this former windmill in Cranbrook fell into disrepair and was eventually looked after by Kent County Council, who refurbished the site with the help of the Society for the Protection of Ancient Buildings in 1960. The mill, which is the tallest smock mill (a type of windmill that has a sloping tower) left in England, has been open to the public since 1982, with further restoration work being carried out to this day.

Details: Open 2.30pm to 5pm. Entry is free.

WILLESBOROUGH WINDMILL, near Ashford

This working windmill just outside of Ashford is offering guided tours for visitors to see the millers’ kitchen and parlour and discover how it all works. The building, which dates back to 1869, will also have a collection of agricultural artefacts on display and kids can get stuck into traditional activities, including making flour using quern stones.

Details: Open 2pm to 5pm, last tour is at 4pm. Adults cost £5, children £2.50.