It starts as a dull rumble in the distance, a sense of something creating enormous yet invisible power. On drawing closer there is a sensation of vast, incomprehensible forces at work as sheens of mist drift into the sky. Then all at once the full majesty of one of the natural wonders of the world surges into view: Niagara Falls, with hundreds of thousands of gallons of water pouring over every second into the depths of the Niagara River below. It is one of the most stunning sights to be seen anywhere and is the perfect place for adventurers and…