It's embarrassing that what I knew about the Netherlands at my current age is the same as what I knew about Holland when I was four: wooden shoes and windmills.
I didn't even try on wooden shoes when we were there, but we did go to Kinderdijk, which is a UNESCO World Heritage site. I found out about it on a google search, to see if there were any actual windmills still in the Netherlands. Googlemaps said it was about 1.5 hours from Rotterdam by bike, so I thought we could easily do that. Just get a map, hop on our rental bikes, and bike out of Rotterdam, straight to the place. Totally easy.
It turned out to be even easier, because the tourist map we got at the hostel had a dashed line at the bottom, labelled "Ferry to Kinderdijk". We had to ask a few people until we found the ferry, but again, everyone spoke English, so it was easy. The ferry was a great idea, because we not only saved our butts, but we also got a kind of harbor tour on the way there and back.
You have to take a tiny ferry across the river from the main ferry stop.
The windmills in Holland didn't grind grain. I mean, maybe some of them did, but the reason the Netherlands is known for windmills is that they were used to move water. The country is very low (*Nether*lands), close to sea level, so much of it was reclaimed by pumping water out to dry up the land. Hence the saying: "God created the earth, but the Dutch created the Netherlands."
As you could probably guess, there are a lot of waterfowl in the Netherlands.
There is one windmill that is open to the public and that you can get up close to, but not too close. It's hard to see the scale, but that sail is really long.
And when they get going:
From inside the windmill: