To learn more about Canadian attractions (Skylon Tower, Whirlpool Jet Boat Tours, Ripley's Believe It or Not, and Niagara-on-the-Lake), visit Info Niagara.
For details on the Canadian Niagara Parks and attractions, including the Maid of the Mist and Butterfly Conservatory, go to the Niagara Parks website.
The Niagara USA website outlines sightseeing on the American side of the falls.