After traveling 450 miles up the lower Columbia and Snake Rivers, we arrived this morning at Clarkston, Washington. Just across the Snake River is Clarkston's sister city Lewiston, Idaho, the farthest inland seaport in the West. Here we boarded jet boats and continued another 50 miles up the Snake River, into Hells Canyon. This spectacular gorge has walls of columnar basalt and limestone, and is home to several large bands of Rocky Mountain bighorn sheep. Along the way we made a stop at Buffalo Eddy to view these ancient petroglyphs.