Karelia is a region in Northwestern Russia, which borders Finland to the west, Murmansk Oblast to the north, the White Sea to the northeast, Arkhangelsk Oblast to the east, Vologda Oblast to the southeast, and Leningrad Oblast to the south.
Karelia is known as "the country of lakes." One quarter of Karelia's surface is covered by water including about sixty thousand lakes. The second-largest lake of Europe, Lake Onega, is located in Karelia. The largest lake of Europe, Lake Ladoga is partly located in Karelia (together with Leningrad Oblast). Wherever there is land, there are dense forests covering the ground.
Karelia has strong cultural connection with Finland and the Karelians, for whom the republic is named, are a Finno-Ugric group very closely related to the Finns. The western part of Karelia is a relatively recent Russian/Soviet conquest from Finland, and a bit of a sore spot for the Finns.
Everybody understands and speaks Russian, although many are bilingual in Karelian, Finnish, and, on smaller scale, Veps. A traveler could get by with only knowledge of Finnish, as many native ethnic Russians understand a good deal of the language.
Basic English is widely understood by young people. Swedish is relatively popular foreign language too.
There is a daily overnight train from Saint Petersburg, which leaves around 22:00 and arrives in Petrozavodsk around 07:00.
There is also a daily train to Moscow, which leaves at 19:00 and arrives at 09:00
Recently Russian railroads launched a new train between Saint-Petersburg and Petrozavodsk which departs at 18:00 both from SPB and Petrozavodsk and arrives at 22:50. The train has cheap and convenient sitting cars and the price is around 500 RUB. Considering that the traveling time is just 4.50 hrs and that all other trains take 8 hrs and are almost twice expensive it seems to be the best option.
The Solovetsky Islands and Monastery on the White Sea are another nearby UNESCO World Heritage Site in Arkhangelsk Oblast and can be reached by boat from Karelia.
Trains head north from Petrozavodsk to Murmansk.