St. Ellen Mine Park, not far from my work. Straighten, crop, levels... they typical stuff. The key tweak is using Topaz Impression plug-in, which is a rather cool toy. I don't remember which specific preset I used, though.
Here's the SOOC (straight out of camera) version, for comparison:
I really like the iPhone for these sort of low perspective images. It has good depth of field and pretty wide angle (28mm effective).