The Niagara River runs from Lake Erie to Lake Ontario and forms the border between Canada and the United States. Along the way, the river makes a dramatic plunge in a series of three waterfalls that are collectively known as Niagara Falls. (Not to let a good name go underutilized, both towns on either side of the river are also named Niagara Falls.)
On the Canadian side one finds the mighty Horseshoe Falls, a U-shaped waterfall that seems perpetually shrouded in mist – a good source of rainbows on a sunny day. Horseshoe Falls are about 2,600 feet (792 meters) wide, drop some 173 feet (53 meters) and account for about 90% of the water that plunges over the three falls.
On the U.S. side of the river – separated from Horseshoe Falls by Goat Island – are two smaller waterfalls. American Falls are about 1,060 feet (323 meters) wide and plunge some 70 feet (21 meters) before crashing onto a pile of rocks left by a massive rock slide in 1954. Next to American Falls, separated by Luna Island, are the much smaller Bridal Veil falls, 56 feet (17 meters) wide with a vertical drop of about 78 feet (24 meters) to a jumble of fallen rock. In both cases, after crashing on the rocks, the water continues a downward path until it reaches the river (so one can debate whether the height of the falls on the American side should be measured from the surface of the river, or the falls first contact with the rocks).
Visitors to the area can experience the falls in many ways. For the most panoramic views of all the falls, one simply has to stroll along the Canadian side of the river through Queen Victoria Park (and enjoy the well-tended gardens as a bonus). There are several platforms that offer elevated views. It is an easy walk from Rainbow Bridge (which connects Canada and the U.S.), past American Falls and to areas that are actually behind Horseshoe Falls. The Canadian side also offers Skylon Tower, 520 feet (160 meters) high, that overlooks the falls, plus a number of very large hotels along the river that provide aerial views. There is also an underground path with openings that provide views from behind the falling water. And, of course, there are the famous Maid of the Mist boats that take visitors along the river to the foot of the falls.
Seeing the falls from the U.S. side is a bit more of a challenge. One can walk through Niagara Falls State Park, including Luna Island and Goat Island, but generally one is standing next to, or behind, the falls instead of looking directly at them. To provide somewhat of a better frontal view, the park includes an observation tower with a cantilevered platform that allows visitors to walk out and look back at the falls. From Goat Island, visitors can also descend by elevator to Cave of the Winds and venture out along a (very wet) walking path at the foot of Bridal Veil Falls. For an aerial view, helicopter rides and ascending it a tethered helium balloon are also available.
While a visit to Niagara Falls – either the Canadian or U.S. side – offers spectacular views of mighty waterfalls, visitors should be prepared for lots of development and tourist schlock. The massive hotels on the Canadian side seem at times to overwhelm the falls. It would have been nice if the area around the falls had been developed more in line with the development around Victoria Falls in Africa, the world's largest in terms of water volume and width, or Iguazú Falls in South America. In both cases there are hotels, restaurants and other tourist infrastructure nearby, but they are not visible from the falls themselves, which are surrounded by large parks that preserve the natural context. But, that's just my humble opinion. Niagara Falls receives millions of visitors each year, so from that standpoint they must be doing something right.