The boat tour into the mist at the base of Niagara Falls has been running in various forms since 1846, and it remains the most viscerally impressive way to experience the falls — not as a curtain viewed from above, but as an enormous presence towering overhead, with the roar amplified and the spray making it impossible to see or hear much of anything. Blue ponchos are provided. They are necessary.
The Canadian-side equivalent, Hornblower Niagara Cruises (same boats, same route), departs from the base of the falls below Clifton Hill. The ride takes you into the basin at the foot of the Horseshoe Falls, where the water hits the river and the mist rises in a permanent cloud. In summer the queue is long; arrive early or book online. The boat can get within about 30 metres of the crest line — close enough to feel, not just see, the falls.