Windmills don't grind grain; they pump water to keep The Netherlands dry.
They were going to demolish the windmills at Kinderdijk because the newer pumps are so much more efficient, but a Dutch princess pointed out that the rest of the world knows only a few things about Holland: tulips, dikes, wooden shoes... and windmills. They kept these 19. Now they can't pull them down because it's a UNESCO World Heritage site.
There is a message told by the way the vanes are parked: horizontal is 'taking a break'; 11:00 is happiness (births, weddings); 1:00 sadness (sickness, death); 9:30/1:30 is 'permanent stop'. These vanes mark the loss of many Dutch aboard MH17. (You're seeing them from the back.)