Either Lütold V von Regensberg or his son Ulrich established the fortified town of (Neu)-Regensberg around 1250. Ulrich died around 1280, and his son Lütold VIII had to sell Regensberg to Habsburg-Austria in 1302. The Habsburgs mortgaged the castle and town several times, and in 1407 the so-called Herrschaft Regensberg was acquired by the city of Zürich. From 1417 the castle became the seat of the bailiff of the bailiwick of Regensberg. On 6 June 1443 the council of Zürich forced their troops and the citizens to defend the fortified town, three days later the castle was conquered during the Old Zürich War by Zürich's contrahents, but not destroyed, and some months later manned again by Zürich troops.
On 9 September 1540 the town, but not the castle, was destroyed by fire, because it was separated from the Oberstadt by a ditch. The upper castle was rebuilt in the following year. From 1689 the castle and the upper town were fortified according to then modern standards. On 13 March 1798 the French revolutionary troops forced the council of the city republic of Zürich to abdicate, and the country bailiwicks were dissolved. After the end of the short-lived Helvetic Republic, Regensberg became the district capital, and the castle was the seat of the cantonal authorities, and in the main building there was the county jail until 1863.
Regensberg was designed as a fortified castle town and built by then modern contemporary criteria. The so-called upper castle (Oberburg) comprises a rectangular plaza as main square which is surrounded two rows of houses, and into the limestone a 57 m (187 ft) deep water well was carved. The lower castle (Unterburg) or lower town (Unterstadt) was probably built in the 14th century nestled at the castle's hill outside of the town wall. Therefore, it was not involved in the modernization of the upper castle in 1689.
Nowadays, the castle belongs to the Regensberg Castle Foundation. The round tower is still open to the public and offers a spectacular panoramic view of the surrounding region. In addition, information panels inside the tower relate the history of the small country town of Regensberg.
References: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.