Merry Andrew...
This link from Spokane, WA goes to a teaching site for kids, but it has some pictures and talks about how many places in eastern Washington state are so similar to Mars that the Pathfinder (and other rovers) have been tested there.
http://www.kidscosmos.org/kid-stuff/kids-boulders.html
NASA/JPL once had a panorama of a site in eastern Washington posted next to a panorama of a site on Mars...you couldn't really tell the difference between the two places...
You could see the brown, dry hills from where my mom grew up. She used to climb them in the summer and she and her friends really did crack eggs on the rocks to watch them cook...
But, when you get near where my Grandma moved later, a little closer to Yakima proper, there was an apple orchard right behind her residential street where everyone had a beautiful green lawn with flower and vegetable gardens.
One of my aunts has a home on a hill where she has a green, grassy lawn, but all around her are the brown hills full of sage brush and other dry climate types of plants.
My relatives have told me that many, many years ago, it used to get quite snowy there during the winters, but anymore they don't get much more snow there than we do on this side.
Guess I should have looked at that site link that I left above a little closer...
Comparison to Ares Vallis Flood Plain - pictures
http://www.kidscosmos.org/kid-stuff/kids-floodplains-comp.html
(more grown-up site below with pictures of the rovers in eastern WA)
Mars Pathfinding in the Channeled Scabland
"This trip shows that Earth is the most Mars-like planet in the Solar System," quipped Jeff Moore of NASA's Ames Research Center. Indeed, the Mars Pathfinder Landing Site Workshop and Field Trips in the Channeled Scabland of Washington proved to be a most excellent experience for the more than 60 engineers, scientists, and educators who gathered to compare Washington with Mars and plan for Mars Pathfinder's July 4, 1997 landing.
"It is exciting that eastern Washington is like the martian landscape!" noted an eighth grade student, Rachel, who came to "Mars Night," a public open house held September 28th to let Spokane residents see what the Mars Pathfinder team was doing in town that week.
It was a virtual invasion of "Martians." The group went to Washington to compare the landscape created by catastrophic Ice Age floods more than 13,000 years ago with the larger Mars flood channel, Ares Vallis. It is in Ares Vallis that Mars Pathfinder will land. The Channeled Scabland of Washington and Idaho represent the best analog on Earth to the channels on Mars..."
story
http://tes.asu.edu/TESNEWS/4_VOL/No_4/scab_adventure.html