Leiden's location puts almost all of the western Netherlands within easy day-trip reach. The bulb fields of Lisse and the Keukenhof gardens, open mid-March to mid-May, are 20 minutes by bus to the north. The North Sea beach at Katwijk and the dunes around Wassenaar are a 15-minute bike ride or short bus from the centre.
The cities of The Hague, Delft, and Amsterdam are all under 40 minutes by train, making any of them an easy half-day if you have already seen Leiden's own centre.
