Where was The Long Ships filmed?
1964 film by Jack Cardiff
The Long Ships (1964) was filmed in Avala and Lim bay, 2 places named in its Wikipedia article, in Croatia, Serbia. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Places per Wikipedia's article
The Wikipedia article names 2 places. Each links to the sentence that says so.
Recorded only at country level
Its Wikipedia article also says it was filmed in United Kingdom, Yugoslavia, without naming a place, so it is not on the map.