The mystery triangle at Trail Crossing A relic of World War II bomber training remains on the Crooked River National Grassland A mysterious triangle is visible from Google Earth on land administered by Crooked River National Grassland just north of Trail Crossing. The triangle is quite large, measuring nearly 950 feet on a side. Only a few were aware that the structure was there. It was even a mystery about why it was there and what its purpose was. The site dates to World War II when Redmond and Madras had Army Air Force Flight training. Redmond was used to train pilots and crew of B-17 bombers and P-48 fighters.