Niagara Falls is one of those places you think you understand before you go. You've seen the photos, you know the numbers — 3,160 tons of water flowing over Horseshoe Falls every second, the mist visible from miles away — and you assume the actual experience will be proportional to the famous image. It isn't. The scale is larger than any photograph communicates.
The Maid of the Mist boats have been running tourist trips to the base of the falls since 1846, making this one of the longest-running tourist operations in North America. You board at the base of the gorge in Niagara Falls State Park, put on the blue poncho they give you, and the boat motors directly toward Horseshoe Falls until you're close enough that the spray requires the poncho to be more than decorative. The roar is physical — you feel it in your chest as much as hear it.
Niagara Falls State Park, on the American side, is the oldest state park in the country, established in 1885. The park includes Goat Island, which sits between the American Falls and Horseshoe Falls and provides access to viewpoints from both sides. Luna Island, a small outcrop accessible by footbridge, puts you within feet of the American Falls with nothing between you and the water.
The Canadian side has the more theatrical view of Horseshoe Falls. The American side has the closer access to the American Falls and the better park infrastructure. If you can only do one side, both make a case. If you have time, do both. The falls are worth it from every angle.