Probably, thinking of a large timespan, the option of doing some kind of "monumentdata", like English Wikipedia's PERSONDATA, would be more useful. And lists could be transwikied easily. But it must be taken into account that not all monuments will ever have an article, and therefore wouldn't appear in the list.
The approach taken in the Catalan Wikipedia has been to get all the data from public websites of the government (in some cases by bot), and then add the coordinates in each case. Of course, it is difficult to update, but most public websites aren't updates regularly (some ever!).
Joan.