Does this look like something out of an impressionist painting to you (minus the tourists)? If yes, you're onto something. These are Monet's Water Gardens at Giverny, that he made while living there, along with his flower garden.
I first heard about them after visiting the Musée de L'Orangerie, famous for the two rooms made especially for his Nymphéas, and it was immediately what I wanted to see next. There was no time during that trip, unfortunately, so it had to wait for the next opportunity, and this wonderful sunny weekend in late Spring with all the flowers in bloom was it.
I don't have much to say about the gardens, I don't think anything can be said. Go there. Find a nice day in Spring, try during the week when the crowds will be smaller, buy tickets in advance so you don't have to wait longer than necessary, take the very first train, or better yet, sleep there (yes, there are cheaper options in Paris, but none quite as charming as Giverny), be at the doors when they open, and you won't even remember to thank me. It's completely understandable.
We were there for nearly three and a half hours that weren't enough, and a quick look at a map will assure you it's not because they're very big gardens, not in size. It takes more than a look to take in all the beauty of them, the life buzzing around - and I don't mean the tourists, it was hard to notice them over the birds and frogs and bees.
If you want to see the water lilies, you should go in July/August (see here what is blooming when, in French), but it's worth it no matter when you go, I'd love to see it covered in snow too.
I've put up all photos here if you'd like to see more, but I warn you no picture can ever do it justice.
Oh, and in case you're wondering where did that photo from the last post go, it was on the way from Giverny to Vernon, I'll tell more about that later :)