Estonia is the smallest and northernmost of the Baltic States. The Estonian people are related to the Finns and have rich ethnic customs, which they have retained, even though they have been an independent country for less than 30 of the last 500 years. For most of the last three centuries they have been ruled by the Russians, from whom they regained their freedom in 1991. The country is mostly flat except for some highlands in the south-eastern corner. Islands off the western coast make up 10% of the country's area.
Growing up and going to school in the 1950's and 1960's, I don't ever remember Estonia or the city of Tallinn being mentioned in our geography classes. Estonia was absorbed by the Soviet Union in 1939 as a part of the Hitler-Stalin pact. The city was cut off to western visitors for over 50 years. I've found through the years that new places that you don't know much about are often among the most interesting.
If your ship is in Tallinn for the day, take the time to go ashore and do some exploring. There are delightful cafes where you can try the local beer, and many shops with English-speaking clerks eager to assist you in spending your dollars!