Niagara Falls - Maid of the Mist boat tour - - (you cannot go to see the falls with out doing this ! ) which is on the American side so if u go to the Canadian side which has a much better view and the boat ride is called the HORNBLOWER
The Samaria Gorge is a National Park of Greece on the island of Crete. A major tourist attraction of the island and a world's biosphere reserve. The gorge is in South west Crete in the regional unit of Chania.