Keukenhof Gardens are the most beautiful spring garden in the world.If you arrive in spring, you'll be luckier. You can enjoy huge fields of flowers in the great outdoors, and--even better--you'll almost inevitably spend half a day touring the Keukenhof International Flower Exhibition, a 70-acre showcase for the Dutch flower industry. For nine weeks every spring, these famous gardens draw more than three quarters of a million visitors to see a changing display of more than 7 million flowers--including some 1,000 varieties of tulips alone.As Dutch history goes, Keukenhof is young. Situated on the grounds of a long-razed castle, inhabited during the fifteenth century by a countess whose four husbands (one at a time) included a dauphin of France and a Duke of Gloucester, it was opened a few years after the end of World War II by a group of bulb-growers intent on exhibiting the splendor of Dutch flowers.