Clemson, SC
The largest private residence in America — 178,926 square feet, 250 rooms — built by George Vanderbilt between 1889 and 1895. The French Renaissance château and its formal gardens are clearly visible from the air south of Asheville. The 8,000-acre estate includes farms, forests, and the Biltmore Winery. The sheer scale is difficult to comprehend until you see it from above and realize the building itself covers 4 acres.
The most-visited national park in the United States — by a wide margin, drawing more than twice the visitors of the Grand Canyon — straddles the Tennessee-North Carolina line along the crest of the southern Appalachians. The "smoke" is real: the dense forest exhales so much water vapor and organic compounds that a blue-grey haze hangs permanently over the ridges. It's one of the most biodiverse temperate places on Earth — over 19,000 documented species, with estimates of many times more, and the salamander capital of the world. The park has no entrance fee (a condition of the land transfer from Tennessee and North Carolina). Cades Cove, a broad valley ringed by peaks with preserved pioneer cabins, and Clingmans Dome, the highest point in Tennessee, are the signatures; the Appalachian Trail runs the crest for 71 miles.
The most-visited unit of the entire National Park System: 469 miles of motor road tracing the crest of the southern Appalachians from Shenandoah down to the Smokies, 252 of them in North Carolina. Begun as a Depression-era public-works project in 1935 and not fully finished until 1987 (the soaring Linn Cove Viaduct around Grandfather Mountain was the final piece), it was engineered for slowness — no commercial traffic, gentle grades, 45 mph, the views unfolding through 26 tunnels and hundreds of overlooks. Around Asheville it climbs past Craggy Gardens, where rhododendron blankets the balds, and on to Mount Mitchell, the highest peak east of the Mississippi at 6,684 feet.
The largest exposed mass of granite in the world — a 825-foot bald dome of solid quartz monzonite rising abruptly from the Piedmont forest 16 miles east of downtown Atlanta. The visible dome is the tip of a pluton that extends nine miles into the earth. The north face carries the largest bas-relief sculpture in the world (190 feet wide, 90 feet tall) depicting Confederate generals Lee, Jackson, and Davis on horseback — a controversial monument carved between 1923 and 1972. The mountain's base is a state park with a lake, gondola, and walk-up trail to the summit. From the air the dome reads as a single bare gray-pink stone in a sea of green.