I came across an article at Design Instruct. Thanks to Jake Gube for sharing these wonderful free photos.
He wrote:
"Here’s a bunch of free landscape stock photos you can download and use for free.
The following images are from Unsplash, Gratisography, Pixabay and Little Visuals — sites that release or feature photos in the public domain. This means these landscape photos can be used commercially.
These landscape images can be used as wallpapers, website backgrounds, stock photos, etc."
Here is a preview of just two of the photos.
http://designinstruct.com/resource/free-landscape-photos/