Longwood Gardens in Pennsylvania. From the Philadelphia airport, take I-95S to 322W to U.S. 1. In 45 minutes, you arrive at Longwood Gardens, about three miles (five kilometers) northeast of Kennett Square, Pennsylvania. Pierre du Pont, who reshaped the family company for the 20th century, found spare time to personally design Longwood Gardens (www.longwoodgardens.org). The property includes forest rambles and walks in Italianate gardens. The conservatory, with 4.5 acres (1.8 hectares) under glass, nurtures 5,500 kinds of plants, including a room of orchids. In the 1930s, Pierre created fountains that still leap and sway with an evening light and music show.