What does a windmill do exactly?

What are the defining symbols of countries? Australia and Uluru, the Opera House? The US and the Statue of Liberty, the Empire State Building? France and the Eiffel Tower?

Think Holland and (unless you have spent too much time in an Amsterdam 'coffee' house) a windmill probably springs to mind. And rightly so - this distinctly olde worlde symbol of a quieter, gentler age is as Dutch as clogs and tulips.

But what does a windmill do?

Yesterday Api dropped us off at the 'Kinderdijk' to find out!

The Kinderdijk is an array of windmills north of Dordrecht. It is listed as a World Heritage site by UNESCO for its cultural value.

We joined a sprinkling of late season tourists walking along the canal where 19 of these old beauties sat quietly, tolerating our gawking. The only noise was the sound of a thousand electronic camera shutters, as we vied to be photographed with an icon over our shoulder. Think Uluru, Empire State, Eiffel Tower.......

We got inside one for 12 euro. And that's when their purpose became clear - each is a gigantic pump - a massive, wind-driven machine, huge, powerful, noisy, complicated, scary. Enormous oak transmissions convert wind-power to rotation, driven down through the mill on a metre-wide oak beam to another timber-toothed transmission that drives the water-wheel.

And these monsters were home to the mill family that would rig the sails, winch them to face the wind, spend their lives inside the bowels of this massive contraption. And, I'm betting, occasionally get their blocks knocked off if they stopped to admire the view and neglected to duck.

This gigantic array of machines pumped billions of liters of water, lifting it up to drain the lowlands - as in below sea and river level -  that would otherwise be flooded and unusable. And they worked from the 1740s until the 1950s until shiny electric water-screws took over. Sorry, don't have any photos of them - but did get a few of the windmills!