MOSCOW and BEIJING are popular tourist destinations.
Tourists visit National or State PARKs (like MAMMOTH Cave).
Tourists might visit a COURTyard, or Hampton COURT.
Tourists visit religious relics, like a fragment of the CROSS.
You might go on a LEPRECHAUN tour in Ireland.
POLICE try to keep tourists safe.
My favourite possibilities for the final word:
Leprechaun - this bit of Irish culture seems to be exploited ruthlessly for all the tourism it can generate
Park - tourists might visit them, I guess
Mammoth - might be a tourist attraction at a natural history museum
We definitely need to guess our third word here, given the game state. Time for a bit of theory-crafting.
I suspect the plan was Tourism 4, as Spot goes quite well with it. If so, our largest clue was going to be last. This suggests that the answers are a fairly strong match: otherwise, clue it earlier and we have some spare guesses to catch up. It's also possible that there's a blocking word that WK was hoping red would remove first (or one of our answers unblocks an easy clue for red, I guess).
Hmm, not sure that really helps much. Anyway, I'm looking most favourably on Leprechaun for the third.
Reading DaveV's spoiler:
Some good thoughts there. I hadn't considered National Parks... and I seem to recall they generate tourism in Civ 6. Given where we're playing, I think that makes Park my strong preference for the third word.