An amazing thing about Amsterdam is that, in 10 minutes (by bike or public bus), you can be in the wide-open polder land -- the vast fields reclaimed from the sea where cows graze, tiny canals function as fences, and only church spires interrupt the horizon. A fun way to experience this is by canoe with a local guide. And that's the mission of Majel Tromp, a friend who runs Wetlands Safari (which I've recommended in my guidebook for many years). In a couple of months, I'll be taking my film crew on a canoe ride with Majel.
In this natural preserve, the water is shallow. When you stick your oar into the mud and twist you wring bubbles out of the sod: methane -- natural gas. (You can smell it.) And, sticking a pole into the ground, you discover the "land" is thin -- about a meter thick before you hit the water table underneath. The ground is just a mat of vegetation, and below it is the inland sea -- and when you throw your weight around, the world becomes your own private trampoline.