Take one snow-covered icy bridge, one part rusting broken handrails, a raging river ending at Niagara Falls and you have a wonderful location for an afternoon stroll.
Picture this (purely fictional) scenario: You have to walk maybe 200 meters across a narrow catwalk raised above quick-moving water. The railings are rusting metal, most of which are falling down. The catwalk is covered in slippery ice, and then that is covered in snow (hiding the slippery bits). And, if you fall off into the water, in about 30 seconds you go over Niagara Falls.
And added to all that, you shouldn't be spotted because well, you're probably not supposed to be on that catwalk anyways. :)
That being said, Andrew deserves special thanks for encouraging the visit to this place. It's been one of the most memorable places I've ever visited.