####TL;DR, to re-visit and barring large countries: Argentina, Morocco, and Portugal

Top 3 in general or to re-visit?

For example, Iceland is one of the top for sightseeing nature but it's not high on my list to re-visit as I've already been thrice (once was before it blew up on social media so it was empty of tourists but the infrastructure wasn't nearly as good as now). My proximity to places visited also factors into how low it is placed in places to re-visit. EG., I love theme and amusement parks but Florida (more on this vs. US later) won't necessarily be high on the list since it's in relatively close proximity.

Additionally, everyone travels differently. Some go primarily for natural beauty, others for history, to party, for relaxation, etc.

Then how would you even rank them? The amount of breathtaking sights and experiences is the first to come to mind. If that's the metric, I think it's unfair for the large countries such as Canada/China/US as they have such a wide variety of diverse landscapes (and in the case of old civilizations like China, history) but are clearly infeasible to see it all unless you take months off work. As such, I like to separate the provinces/states into their own "country" since, as a more extreme example, the province of Québec can fit France, Spain, Germany, and Belgium within it. Otherwise the top 3 in general would probably be...Canada, China, and US lol if I had unlimited time and funds.

Anyways, back on topic and with my country restrictions. These three countries I've only ever visited once, have very distinct atmospheres, stayed between 1-2 weeks in each, loved my entire time in them, and would not hesitate to go again if asked (in alphabetical order as I'm sure you can tell by now): Argentina, Morocco, and Portugal

Edit: Yes, Canada and US also has history but in terms of structures, there's something different between standing in front of the 2,000+ year old Al-Khazneh and the 137 year old Statue of Liberty