Longwood Gardens sits on over 1,000 acres and attracts over one million annual visitors. Varied outdoor gardens range from formal to naturalistic in design, and 20 indoor gardens are located within a group of heated greenhouses. Longwood's Conservatory contains 4,600 different types of plants and trees, as well as fountains. The Gardens also have extensive educational programs, and host hundreds of horticultural and performing arts events each year, including an extensive Christmas light display during the holiday season. Also on the grounds is the Peirce-du Pont House, the oldest structure at Longwood built in 1730. The core of the original brick house is an outstanding example of Federal-style architecture.