In Poland you don't pay gains tax on real estate if you own longer than 5 years. If you own shorter than 5 years you can skip tax when buying another real estate right away. The prices increased 100% in the last 5 years. No limitations for foreigners. Please come buy and invest to make the bubble spectacular. People needing a place to live cannot afford anymore so it doesn't matter.
Switzerland doesn't have capital gains tax, except for real estate.
Where in the developed world do you get untaxed gains on anything? Not even the USA has untaxed gains... Many loopholes if you are rich but you probably don't have access to those mechanisms.