Transnistria, in English, Trans-Dniester - is a de facto state in Eastern Europe that has declared independence from Moldova, although it is only recognized by the other breakaway states of the former Soviet Union — Abkhazia, Nagorno-Karabakh and South Ossetia. It roughly corresponds to the territory between the Dniester River and Ukraine.
Transnistria (official name Pridnestrovian Moldavian Republic) declared its independence in 1990, entailing a civil war with the much larger successor state of the Republic of Moldova that lasted until 1992.
Transnistria is a product of the messy breakup of the Soviet Union, when a part of the newly formed Republic of Moldova that wanted to stay in the Russian family, rebelled against Romanian language domination from Kishinev and decided to go its own way.
While the country is not officially recognized by any other sovereign nation (not even Russia), the government does effectively control the territory it claims to rule, although their actual wiggle room is perhaps a bit limited by the will of Russia their biggest benefactor and political de facto ally. It maintains its functional autonomy with military and other support from Russia.
While Transnistria is not a classical tourist destination per se, it does offer a certain Stalinist charm and is one of the few "countries that don't exist" (at least according to the UN) that isn't in or close to an active war zone. You can thus boast of having an entry stamp in your passport and banknotes in your wallet that the rest of the world claims don't exist and are invalid. And if it isn't for bragging rights alone, that you come visit there are actually some other attractions as well.
Currency Transnistrian rouble
Country code +373
Time zone UTC+2