We were walking along the Green River in the Mammoth Cave National Park. This is a large park both above and below ground and there are miles of hiking trails and horse back trails. This trail led off the plateau down to this river with deep forest and decent cliffs on one side of the water. Steamboats used to bring tourists to the area and docked near where we were. What caught my eye were the emerging leaves - spring green agains the deeper, green, brown-tinged Green River. An early sign of spring at a higher altitude in the Cumberland.