After the Sweden's defeat in Russo-Swedish War 1741-1743 (also known as the Hats' Russian War) eastern border of Finland was moved to west. Important fortresses of Hamina, Lappeenranta and Savonlinna were left to Russian side of border.
The city of Loviisa was established in 1745 to handle a international commerce in Finland. Planning of the new fortification system started concurrently, because Loviisa was located alongside the strategic road from Vyborg to Turku. The parliament accepted the plan of twin fortresses in 1747: one in Loviisa city to protect the road and another to Svartholma island to defence Loviisa from the sea. Building of the Loviisa fortress started in 1748, but the plans were never completed. The ground was too muddy for heavy stone walls and the Crown had continuous lack of money. Building was interrupted in 1757 and the king Gustav III ordered to stop the construction permanently in 1775. Loviisa fortress didn't see any battle. In the Finnish War 1808-1809 it surrended to Russians without fighting, because people of Loviisa were afraid of the destruction of the city.
Nowadays there remains two completed bastions, Rosen and Ungern. Renovation started in the 1960's and Ungern is mostly renovated. Rosen is still uncompleted and mostly ruined.
The Seaplane Harbour is the newest and one of the most exciting museums in Tallinn. It tells stories about the Estonian maritime and military history. The museum’s display, that comprises of more than a couple of hundred large exhibits, revitalizes the colourful history of Estonia.
British built submarine Lembit weighing 600 tones is the centrepiece of the new museum. Built in 1936 for the Estonian navy, Lembit served in the World War II under the Soviet flag. It remained in service for 75 years being the oldest submarine in the World still in use until it was hauled ashore in 2011. Despite its long history, Lembit is still in an excellent condition offering a glimpse of the 1930s art of technology.
Another exciting attraction is a full-scale replica of Short Type 184, a British pre-World War II seaplane, which was also used by the Estonian armed forces. Short Type 184 has earned its place in military history by being the first aircraft ever to attack an enemy’s ship with an air-launched torpedo. Since none of the original seaplanes have survived, the replica in Seaplane Harbour is the only full-size representation of the aircraft in the whole World.
Simulators mimicking a flight above Tallinn, around-the-world journey in the yellow submarine, navigating on the Tallinn bay make this museum heaven for kids or adventurous adults.
Seaplane Harbour operates in architecturally unique hangars built almost a century ago, in 1916 and 1917, as a part of Peter the Great sea fortress. These hangars are the World’s first reinforced concrete shell structures of such a great size. Charles Lindbergh, the man who performed the first solo flight across the Atlantic Ocean, landed here in 1930s.
On the outdoor area visitors can tour a collection of historic ships, including the Suur Tõll, Europe's largest steam-powered icebreaker.