I hate posting facebook links, but here's a great gallery on the demise of the pavilions of the 1967 world's fair held in Montreal. The pics are kind of on the small side, but worth a browse anyway.
The city tried to keep the fair going (under the name Man and His World) for the next few summers, but the buildings were temporary structures and the whole thing eventually fizzled out. A few pavilions remain, notably the France and Quebec ones which are now the Montreal Casino, and the La Ronde amusement park continues to this day (as a Six Flags property). Today, the Expo islands are mostly parkland, with some festival space for concerts and of course the Grand Prix racetrack.
Enjoy.
https://www.facebo.../10157679912702461 If you feel like reading more about Expo 67, John Whelan's web site is probably the best one out there:
http://expo67.ncf.ca