One of the most spectacular sights in the Bob Marshall is the Chinese Wall. Also known as the Lewis Overthrust, this wall is the result of the geologic upheaval in which Montana split "wide open" from Glacier Park on the north nearly to Yellowstone Park on the south. As the earth’s crust split, the west side tipped up like a roof; the east side slid under the "roof" for nearly 20 miles, forming the Chinese Wall. From the Haystack Mountain area west of the Continental Divide, the view of the 1,000-foot high Chinese Wall is virtually unbroken for nearly 20 miles. The Chinese Wall is home to many mountain goats and mountain sheep. Eagles also make these high cliffs their home, and often glide in the wind currents.