6. Open Monumentendag

The Buzz -- As packed as it is with history, you know there's got to be more to Amsterdam than the usual tours and museums. Well, each September, the curtains are thrown back just a bit further. For one weekend, visitors are allowed to explore the interiors of dozens of buildings which are generally off-limits. Be they age-old fortifications, storage facilities, monuments or secreted-away places, they are explained, described and opened up (albeit briefly) for those with an insatiable curiosity. A rare, unusual opportunity.