2017-09-14 14:43 GMT+02:00 Ynhockey <ynhockey@gmail.com>:
Thanks for the answers. I'll see if it's possible to at partly copy the lists to Wikidata.

The only duplicates I noticed are indeed in Jerusalem, but it's 3 identical sites—which all represent a large ambiguous monument, which in our lists consists of dozens of specific ones.

Not exact duplicates in fact, there is a global item (Old City of Jerusalem and its Walls (Q15726304)) and two more specific (Old City of Jerusalem (Q213274) and Walls of Jerusalem (Q2918723)).
Such divide is not uncommon on Wikidata but here the data are duplicated (and most probably shouldn't, I left a message to the editor who added these data to get an explanation and hopefullly remove the duplicated informations, it should be resolved soon).

If you need help creating items on Wikidata, don't hesitate to ask!

Cdlt, ~nicolas