If Amsterdam was ever overrun by hostile forces, evil doers or ill wishers the inhabitance of the city would be able to rest easy in the knowledge that these invaders would not make much progress, quickly lose motivation, soon give up altogether and returned home in a very disgruntled mood. The reason for this cannot be attributed to any superior tactical advantage or any well designed fortifications that the city has. It is because of one thing and one thing only; moving vans.
A single moving van is capable of blocking an entire canal street thus making passage by bike quite impossible without the risk of running over a pedestrian, cycling into a dinning set, being decapitated by a wing mirror and/or pushed in to the nearby canal by the driver opening the door.
The presents of a stationary moving van usually forces a diversion which will most likely turn out to be blocked itself by another moving van. In fact it is entirely possible to have your attempted detour continually thwarted one street after another until (before you realize it) you are cycling from East Amsterdam to West Amsterdam via Rotterdam. This also means that several moving vans working together could easily shut down entire sections of the city and bring Amsterdam to its knees if they so desired. Moving vans are above the law. They answer to no one. They are the law.
Things get much worse if you are unfortunate or foolish enough to be driving around Amsterdam because a single moving van is also capable of creating very long traffic jams.
If a car encounters a moving van the driver is forced to wait and watch as every piece of furniture is paraded in front of them like some kind of Ikea drive through. Although it might feel tempting it is important to know that beeping of the horn is ineffective at this point, especially if you wish to generate sympathy for your current predicament from those living in the surrounding area.
Only once a moving van has been fully loaded with furniture, unloaded, rearranged to fit an odd shaped sofa, reloaded and the movers have had their fifth tea break (in view) will the moving van finally be ready to move. Victory is usually short lived however as most of the time the moving van just stops again after a few meters to start unloading at the new destination. Amsterdam is a small city after all.