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.
Valamo Monastery - the monastery of the Finnish Orthodox Church. Originally Valamo was placed on an island of lake Ladoga in Karelia but was evacuated whilst in war with the Russians in the 1940s. The monks came with their icons and rebuilt Valamo close to Heinävesi a bit west of Joensuu. The monastery is visited by many Finns, orthodox or not, and is featured in most tourist guides as well. Almost all buildings though are post war and one can't suppress the impression that there is a commercial streak somewhere. However most people come to see the ancient icons from the old Valamo monastery. Boats full of tourists leave during the summer months from Sortavala, Lakhdenpokhya, and Pitkyaranta, as well as big river cruise boats from Saint Petersburg and Moscow. It's also possible to travel here by helicopter from Petrozavodsk.