This 568-acre, 18th-century estate is dotted with lakes, fountains, and a Japanese garden. The centerpiece is the Norman Foster–designed Great Glass House, the largest single-span greenhouse in the world, which blends into the curving landforms of the Tywi Valley. The greenhouse's interior landscape includes a 40-foot-deep ravine and thousands of plants from all over the world. The Ghost Forest is a stunning art installation, made from the carved stumps of ten giant hardwood trees—a powerful statement on how rapidly the world's forests are being destroyed. The grounds have lovely views across the Carmarthenshire countryside, especially from the Paxton's View lookout point. It's marked by Paxton's Tower, a Gothic folly built to honor Horatio Nelson, now owned by the National Trust (it's free to wander, though there's nothing to see inside). The garden, 20 miles northwest of Swansea, is signposted off the main road between Swansea and Carmarthen.