Having been a flatlander for most of my life, Chicago having only small man-made hills and overpasses, I am constantly amazed at the terrain here in Pittsburgh. I’ve been told that all of these hills, valleys, ravines, whatever you want to call them, were created by erosion. In other words, it all began with a high plateau and wind and water created the low points. I am particularly fascinated with the bridges and tunnels men have created to overcome the changes in terrain. One of my favorite structures is this stone arch double bridge. On the right is a railroad bridge; on  the left  is Lincoln Avenue, which passes under the railroad bridge. Just down the road is another spectacular bridge: Larimer Avenue. Both bridges cross a valley traversed by Washington Blvd. Neither street seems very heavily traveled today, but they are the only way to get across the valley for a distance of several miles. I finally drove over both bridges, but they are much more spectacular looking from below.