Archaeological Museum, which is located in eastern Lithuania. It is enough to mentioned that this outstanding museums is listed n the UNESCO list! There is also incredible Kernave Archaeological Site, where you can see remains of the medieval town. For example, if you like the newest history, you should absolutely visit the Paneriai Memorial. This museum is dedicated to the victims of the Holocaust. What is more, there is also the KGB museum (also called the Museum of Genocide Victims). This museum is dedicated to the history under the Soviet rule as well as to repression against Lithuanian citizens.
To visit the second country, which is a paradise for history lovers, you can take one of many cheap flights to Russia. When you are there, you will have a chance to visit places and sites where many important historical events took place (http://www.lot.com/airline-tickets/flights-to-russia). For instance, if you visit St Petersburg, you can visit the Church of the Saviour on Blood, which was built on the spot where Tsar Alexander II was assassinated in 1881.