I'd like to build a list of popular points of interest and tourist attractions for many/every city in the world. Is there any sort of dataset that I can use for this which either contains only popular attractions, or something like the OSM data with a popularity index that I can filter through myself? Open or Free is preferable.
I've tried playing with FourSquare's API, but it is against their TOS to save any of their data for longer than just caching. It was also common for things like a Starbucks to appear in the list of most popular locations, but this wouldn't be too troublesome to work around. (I guess because more people want to check-in at Starbucks than a Museum).
I'm looking through OSM at the moment, but there doesn't seem to be any indication of the popularity or importance of a POI. The tags are nice, but not very helpful to me if there is no way to differentiate Disney World from a touristy taco-shack.
Thanks in advance for any help or direction.