It’d make sense to put the UN on an island that would then be ceded to the UN.
Hans Island would be ideal as this act would also resolve a long running dispute between Denmark and Canada.
Why? What did Canada ever do to you?
The French have some suitable islands in the Southern Indian Ocean...let them look after it for a change.
What if the UN was situated on an island and it was it's very own nation !
UNistan
They could develop their own police force and fire department ... hell, they could even have a congress to vote money for themselves !!
They can have the knotted gun as a parting gift from us.
Quemoy (Kinmin) or Matsu get my vote. Or perhaps the Diaoyu Islands, with all rent money going to Japan.
How about Cyprus? That would get the Turks panties in a wad!