Niagara Falls is a sight to see, but located south of Seneca Lake in the Finger Lakes region lies a lesser-known fantasy-like area called Rainbow Bridge and Falls in Watkins Glen State Park, New York. Maybe on Montreal trip?
Gorges de l'Areuse, Switzerland The Val de Travers is a Jura mountain valley perpendicular to the main valleys (hence the name). The river Areuse has cut itself steeply through the soft limestone and clay sediments. It's one of those Roman bridges too.
South Wales, Australia - the Disused Helensburgh Station - opened in 1889 and operated for 26 years before closing in 1915 and a newer facility opened. The tracks and tunnel are still in place almost 100 years later, but overgrown by nature.