The Baltic States are three countries of Europe, with a long history and diverse culture between regions. The three countries were independent, then occupied by the Soviet Union, but they were among the first to break away in 1990—91 and today are members of both the European Union and NATO.
North to South:
Kaliningrad Oblast is a small exclave of Russia, between Lithuania and Poland. You need to get a Russian visa and proceed through customs to enter Kaliningrad Oblast (nationals of 53 countries are eligible to apply for a free Kaliningrad eVisa).
The Baltic states did have a vibrant history. A substantial part of the region was part of the Polish-Lithuanian Commonwealth. Later, they were briefly independent until they were occupied by the Soviet Union. The Baltic states then regained their independence.
Cultural, ethnic and linguistic relations
Despite the three nations' similarities in history, politics and geography, their languages and culture belong to two distinct language families. The Latvian and Lithuanian languages make up the living members of the group of Baltic languages, spoken by the ethnic Balts in the region, which belongs to the Indo-European language family.
The Estonian language, on the other hand, is a non-Indo-European language and instead belongs to the Baltic-Finnic subgroup of the Finno-Ugric languages, sharing close cultural and historical ties with the Finnish language and culture.
Estonian, Latvian and Lithuanian are neither mutually intelligible with each other nor with any other foreign language.
The peoples of the Baltic countries also belong to different Christian denominations. Primary denominations are Orthodox (Estonia), Lutherianism (Latvia) and Catholicism (Lithuania), however there are people of all these denominations (and others) in each country.
Religious adherence is the greatest in the south of these countries, mainly Lithuania, and least in the north (particularly northern Estonia).
Each of the three Baltic countries has the language of their respective titular nationality as an official language. Any attempt to speak the native language will be greatly appreciated.
Russian is understood by the majority of the population in all three countries. Some tourists have experienced hostility when speaking Russian, particularly in rural areas away from Russia (where few are of Russian descent), however most major cities have large native Russian speaking populations.
English is increasingly spoken as well, especially by the younger generations. German is also understood by a sizeable minority. Finnish is understood by many in northern Estonia due to access to Finnish broadcasts and heavy tourism, and some Polish is also spoken in border areas of Lithuania.
Riga Airport (RIX) is by a large margin the busiest hub in the Baltic countries, and is also the main hub for AirBaltic  which connects to around 60 other European cities. The airport also serves a single intercontinental route to New York (JFK) with Uzbekistan Airways . Tallinn Airport (TLL) is hub for Estonian Air ] as well as a secondary hub for Air Baltic along with Vilnius Airport (VNO). Czech Airlines, Finnair, LOT Polish Airlines, Lufthansa and Norwegian flies to all 3 airports.
The international bicycle project, BaltiCCycle  may provide you with a lot of information and help.