Niagara Falls is one of the world's natural wonders, and for good reason. It is the fastest flowing falls on the planet, emptying more than 28 million litres of water over the 51m (171ft) high rim every second. The water forms a pool beneath that is slightly deeper than the falls is high. The roar of the water and the mist rising above the horseshoe is breath taking. An estimated 40 million visitors come from all over the world to witness this spectacle. This is greater than the population of Canada. The falls are located on the Niagara River which borders Canada and the United States of America. Small islands divide the falls into three distinct sections. Below the falls, water rushes through the Niagara Gorge at an incredible 60km/h (40mph) making this a class 6 rapids that is deemed unpassable, even for experts. Although a few people have successfully swam the river or navigated through in a boat, these attempts have often ended in tragedy. Crossing the falls, going over the falls, or entering the river is now illegal and violations are strictly enforced. The risk to the public and also to first responders tasked with rescue efforts has been determined to be intolerable. Numerous attractions at the falls help visitors experience the magnificence and power close up. The Hornblower is a boat tour on the Canadian side that takes guests to the edge of the cascading water beneath the falls. Even the rain jackets provided will not prevent a good soaking for those adventurous enough to go to the bow of the boat. The Maid of the Mist on the American side of the falls provides the same tour from their dock. Plaques on the walls provide historical accounts of daredevils who have challenged the falls and won, as well as the many who have perished. The great beauty and unsurpassed magnificence of these falls inspires awe, while the sheer power and force commands respect. A trip to either side of Niagara Falls is something that will not be forgotten.