Leiden is close to my heart, as I lived there twice and my daughter was born there. I still need to build a proper Leiden page but some information can already be found on my Leiden page.
Leiden, among other features, is the oldest university city of The Netherlands.
The Pilgrim Fathers also had something to do with Leiden...
See the link to my Leiden page below.
Although my Noordwijk page has no really worthwhile tourist info yet, it is a place that I will always remember as my brother lived for 25 years in the WIllem van den Bergstichting. It is a village in itself for mentally handicapped.
Noordwijk aan Zee is a real beach resort and I've spent many happy weeks there as a child.
See the link to my Noordwijk aan Zee page below.
Like Zoetermeer, Leidschendam is mostly modern with a very small older, not too well-maintained center. It has great potential though, once the city council decides to invest. The main feature is the sluice with the two bridges that are worked by hand.
This museum has famous paintings by artists who typified of Dutch and Flemish art in the 15-17th . Our tour guide said that if you see those paitings here, you don't need to see anything in Netherlands( it's too much to say it). Actually "The anatomy lesson of Dr. Nicolaes Tulp" by Rembrandt and "Girl with a pearl earring" by Vermeer are worth seeing.
If you know Noordwijk aan Zee, which like Katwijk aan Zee are both seaside villages, you'll be surprised to see 'just' inland the village of Noordwijk itself. Such a different and quaint atmosphere.