While we were in South Dakota we went for a ride in the Black Hills on the historic Mickelson Trail. It's an approximately 109 mile hiking/biking trail on a former Burlington Northern railway that they stopped using in 1983. We did a 20 mile round trip starting at the Mystic Trail-head and rode 2 miles past the Rochford Trail-head because we wanted to ride through a 2nd tunnel. The 2 trail-heads we rode between were quite scenic and the whole route has 4 tunnels and many trestles and 1 waterfall which we got to see. The particular part we were on ran beside a creek most of the time. Parts of it were through rock cuts such as this one the hubster is going through when I took this image and you can kind of see how the Black Hills were named with the dark rock. It was great fun. The first 10 miles were the hardest because they were mostly all uphill but only a 4% grade at most. It was nice on the way back because it was mostly downhill. :-) We had a water bottle and camera equipment in our backpacks. I would love to do it again sometime and see more of the trail.