A friend just went to Longwood Gardens in Kennett Square, PA (1/2 hour away from Philadelphia) and sent me these pictures. I have been there as well years ago and the gardens are incredible. Here is some history:

Exquisite flowers, majestic trees, dazzling fountains, extravagant conservatory, starlit theatre, thunderous organ—all describe the magic of Longwood Gardens, a horticultural showstopper where the gardening arts are encased in classic forms and enhanced by modern technology. Many generations helped create Longwood Gardens, but one individual—Pierre S. du Pont (1870-1954), industrialist, conservationist, farmer, designer, impresario, and philanthropist—made the most enduring contribution.
Pierre du Pont was the great-grandson of Eleuthère Irénée du Pont (1771-1834), who arrived from France in 1800 and founded the E. I. du Pont de Nemours and Company gunpowder works. Pierre turned the family business into a corporate empire in the early 20th century and used his resulting fortune to develop the Longwood property.
More than 200 years earlier, the land had been inhabited by the native Lenni Lenape tribe who hunted, fished, and farmed the productive wilderness. In 1700, a Quaker family named Peirce purchased the property from William Penn and soon established a working farm. Joshua and Samuel Peirce began planting an arboretum on the farm in 1798. The farm was purchased in 1906 by Pierre du Pont so he could preserve the trees, and from 1907 until the 1930s Mr. du Pont created most of what is enjoyed today. In 1946, the Gardens were turned over to a foundation set up by Mr. du Pont. After his death in 1954 Longwood’s first director was hired. Since that time Longwood Gardens has matured into a magnificent horticultural showplace filled with countless opportunities for enjoyment and learning.
Longwood owes its present-day success to the Peirces, who actively pursued a Quaker interest in natural history. By 1850, the site was known as one of the finest collections of trees in the nation, and one of the first public parks, and its aesthetic qualities were as important as its botanical significance.