Of course no one can think of Holland and not think of Tulips! Amsterdam has the world's only floating flower market, called Bloemenmarkt, located in central Amsterdam. It's quite beautiful, and worth a stroll when you are in Amsterdam.
You can get some quite beautiful photos of flowers when you're there!
During the 17th century, a bubble was formed in the Tulip exchange, causing the price of Tulips to exceed 10x the average craftsman's yearly wages.Tulip Mania.
Munttoren (Munt Tower), originally part of the city wall.