Olafsborg fortress was built in 1475 in case of war with the Novgorod Republic. In the 15-16 centuries, several wars took place, but the location of the fortress in the middle of the lake made the siege almost impossible, and the Russian troops could not capture it.
Gradually, a town began to grow around the fortress.
In the following centuries, the war continued, although it was never captured by force. A distinctive feature was the ability to withstand artillery of the time. Several times the garrison surrendered after a long siege.
Currently, the fortress is the northernmost medieval castle and hosts a museum.
You can get into it through a drawbridge.
Around the castle is a beautiful promenade. There are cafes and restaurants, the city is cozy and is suitable for strolling. There are also sightseeing boats.
There are several streets with wooden houses, but town mostly filled with the modern stone buildings.
We traveled by car and spent the night in Savonlinna. Found a very unusual place Holiday Home Harmaalokki (booking.com). This is a small cottage on the lake, a great place to meet the sunset with wine. Just be careful, we took the keys in a completely different place, got the address by email.
In fact, this is not even a house, but a sauna with folding sofa. Great place to stay with a car.
Getting there: by train from Helsinki (4.5 hours) or by bus (https://www.matkahuolto.fi/en). Free parking in the center of N 61 51.857 E 28 53.733. It takes about 5 hours to travel from St. Petersburg by car.