XB-70 The Return To Valhalla is a look back at the XB-70 Valkyrie and the amazing program that could have, should have been. However, due to politics and a major accident, the program was canceled. "The Return to Valhalla" is a fresh look at the XB-70 Valkyrie and the program. With the addition of many new color photos and images of the new Research and Development Gallery that now houses the XB-70 permanently at the National Museum of the U. S. Air Force, Dayton Ohio, this book gives a fresh look one of the most beautiful and graceful aircraft ever to grace the skies .