Skerries Mills, Skerries, Co. Dublin

The whole assembly, sails and all, stands 41 feet high, with the four canvas sails sweeping a diameter of 53 feet 4 inches, a scale that becomes more striking once you consider how modest the building looks from a distance, a plain round tower of coursed rubble limestone with small square-headed windows tucked into thick walls.

The mill dates to around 1525, which places its origins firmly in the late medieval period, a time when windmills were being adopted along parts of the Irish coast to exploit steady sea breezes for grinding grain. Inside, the mechanism follows a logic that would have been familiar to millers across Europe for centuries: the windshaft, resting on a stone bearing, carries a break wheel that engages with a lantern pinion, a simple gearing arrangement of wooden pins and rollers, transmitting the sails' rotation down a central shaft to drive a single pair of grinding stones below. It is a compact, almost elegant piece of engineering, all timber and stone, with no metal gearing to speak of, relying instead on the friction and interlock of shaped wood. The building was restored around 1995, work that returned the thatched wooden cap and its hardwood bearings to working order, along with the timber shutters on the windows and a reproduction timber door leaf set into the square-headed doorway.

Visitors approaching the mill today are looking at a structure that has been deliberately brought back to functioning condition rather than simply preserved as a ruin, so the sails, the lufted cap, and the internal gearing can all still be seen operating as they would have centuries ago. The thatch itself is worth a second look, since a conical thatched cap on a stone windmill tower is an unusual survival in Ireland, most later mills having switched to boarded or slated caps. The rubble limestone walls, with their small deep-set window openings, are typical of a building designed to withstand constant coastal wind rather than to let in much light, and standing beneath the sails when they are turning gives some sense of the sheer scale of the mechanism driving those grinding stones far below.