Lying 32km (20 miles) northwest of Swansea, this mammoth project is the first modern botanic garden in Britain dedicated to science, education, and leisure. A project costing £45 million, this 229-hectare (568-acre) Regency estate was developed by financier William Paxton in the late 18th century, with walled gardens, lakes, and cascades. Its centerpiece is a magnificent Great Glasshouse, the largest single-span greenhouse in the world, blending in naturally with the rolling and bucolic Tywi Valley. The greenhouse is dedicated to threatened Mediterranean climates of the world, and its interior includes a ravine, rock faces, bridges, and waterfalls.