The Union won its first major Civil War victory at Fort Donelson. The surrender of Fort Donelson, together with the capture of Forts Henry and Heiman, forced the Confederacy to abandon Nashville and give up southern Kentucky and much of middle and west Tennessee, while opening the Tennessee and Cumberland rivers as avenues for Union penetration into the Confederate heartland. It was here that Ulysses S. Grant gained national prominence and earned the nickname "Unconditional Surrender" Grant. The site includes the remains of Fort Donelson, the upper and lower river batteries, outer rifle pits, the Dover Hotel where the surrender was arranged, and Fort Heiman in Kentucky. Intended to help defend the vulnerable Fort Henry, unfinished Fort Heiman was abandoned at the start of General Grant's February 1862 offensive, and remnants of it can still be seen. Fort Henry, built to guard against Union ship traffic on the Tennessee River, was susceptible to infantry attacks and spring flooding; its remains are now under Kentucky Lake, and only the fort's eastern rifle pits remain above water as part of Land Between the Lakes National Recreation Area.