Bob Kersey ©Stars and StripesSouth Vietnam, August, 1967: A Seabee from Naval Mobile Construction Battalion 4 works on the "Liberty Bridge" across the Thu Bon River, 20 miles south of Da Nang. The 2,040-foot span in the An Hoa Valley was designed to support up to 60 tons, allowing the free movement of the heaviest military equipment through the hotly-contested area.