[Image: Algodones Dunefield, California].
While looking for images for the previous post – like this one – I got lost in an amazing website full of unbelievably beautiful landscape images: it's NASA's Earth Observatory page.
Here's a representative sampling.
[Images: Lake Nasser; Colorado River Delta; and the Taklimakan Desert].
There are roughly 1800 other images to choose from, and it appears to be updated daily – good luck.