Fort Henry, part of Land Between The Lakes National Recreation Area, stood 12 miles west of Fort Donelson on the eastern bank of the Tennessee River as a five-sided, open-bastioned earthen fort built to guard against Union ship traffic. It was vulnerable to infantry attacks and spring flooding, however, and it fell easily to the powerful Union gunboat flotilla during the February 6, 1862, attack. Its remains now lie beneath the waters of Kentucky Lake, created when the Tennessee River was dammed in the 1930s, though the outer defenses remain above water and are still visible. The Civil War Sites Advisory Commission has designated it as one of the Civil War's principal battlefields. Intended to help defend it, the unfinished Fort Heiman was abandoned at the start of General Grant's February 1862 offensive and never fired a shot, though remnants can still be seen. Fort Donelson, the site of the North's first major victory of the Civil War, preserves the remains of the fort itself, two river batteries, outer rifle pits, and the Dover Hotel where the fort's surrender was arranged.