For two months every year, the "kitchen garden" (as Keukenhof translates) boasts a spectacular 65-acre/25-hectare array of more than 6 million tulips and other flowering plants. Miles/kilometers of paths wander through some of the most beautiful gardens in the world.
Pick out a plant, and when it has finished blooming, the bulb will be mailed to you. The gardens are open daily from late March to late May. Keukenhof is 20 mi/30 km southwest of Amsterdam. If you are going on a day trip from Amsterdam, take the train from the Centraal Station to Leiden, where you can get a bus to Keukenhof. http://www.keukenhof.nl.