If you travel to Vilnius, you can spend one day in the city of Kaunas. It's still nice to visit another city. Around the Town Hall, a lot of cute streets with an old architecture. From here, you can walk into the St Michael the Archangel Church. It's not really far. This is the main axis of the city.
Places to see
House of Perkunas
St Michael the Archangel Church
Capital City Vilnius Languages Lithuanian, Russian, Polish Currency Litas