Built on an island at a connection point between two lakes in lies a stunning 15th century three-tower that looks like something out of a fairytale.

Still standing after nearly 550 years, Olavinlinna or St. Olaf's Castle, is the northernmost medieval stone fortress in the world, lying about 220 miles from Helsinki.

As the origin of uncountable stories and the site of numerous battles, Olavinlinna Castle is one of the best-known sights in Finland, located on one of the thousands islands of Lake Saimaa.

now get to explore its war-weathered walls as they consider the fascinating story of its founding.

It was the year 1475. Ivan the Great, considered the first tsar, builder of the Kremlin, and known for the great conquests of his expansion campaign (which laid the foundations of what is now Russia), threatened to invade the Kingdom of Sweden.

Erik Axelsson Tott, a nobleman, ordered the construction of a fortress over a network of lakes and canals to protect against any attack.

And so Olavinlinna Castle was founded, whose water flows so swiftly through the channels surrounding the castle that they do not freeze in winter, eliminating the possibility of accessing it on foot even when the cold turns water into ice.

Although the main part of this fortress was completed at the end of the same 15th century, it was reinforced in the 1520s by order of Swedish ruler Gustaf Vasa, and about a decade later, in 1534, it became an administrative centre, housing 200 people at that time.

Despite withstanding numerous Russian attacks during the 16th and 17th centuries, Peter the Great, Russia's first emperor, arrived in the city of Savonlinna (where the castle is located) at the head of an army in 1714.

After six weeks and 5,000 cannon shots, the Swedes eventually surrendered. Russia took over the castle in 1743 and remained there until the mid-19th century when it began to be used as a prison.

Today, although it has been renovated and restored several times, it retains almost all its original structure. Although two of the original three towers were demolished, two others were built so that the number remains unchanged.

Today, Olavinlinna remains a popular tourist destination year-round. In addition to guided tours, many events occur in Olavinlinna, including boxing matches or the Savonlinna Festival - first held in 1912 and held annually since 1967 - which lasts a month and attracts up to 70,000 spectators, 10% of whom are foreigners.

The summer of 2025 concert will mark an incredible 550 years of the world's northernmost castle and is set to feature 89-year-old Finnish composer Aulis Sallinen's movingly beautiful chronicle, Linna vedessä (The Castle in the Water), setting a text by poet Lassi Nummi, as well as something completely new.

Antti Auvinen, the most talked-about Finnish composer of the moment, will write a piece for the castle that will be premiered at the concert.

Olavinlinna is open Tuesday through Sunday except on holidays. From Tuesday to Friday, visiting hours are from 10am to 4pm, and on Saturdays and Sundays, access is available between 11am and 4pm.