Flakfortet, meaning sand-shoal fortress, is a sea fort located on the artificially built island of Saltholmreb. Flakfortet was the last of three artificial islands that the Danes created to defend the entrance to Copenhagen's harbor (the other two are Trekroner Fort and Middelgrundsfortet). Eventually Flakfortet became more of a site for anti-aircraft weapons than for coastal artillery. Its military functions ended in 1968.
The fort was built in the years 1910–1914 as part of Copenhagen's sea-fortifications. The island is 23 meters high and covers 32,000 m2. Construction of the artificial island required the use of caissons of reinforced concrete, possibly the first use of such structures. The caissons were first cast at Lynetten quai on Refshale Island, thought the last was cast at Flakfortet itself.
Flakfortet is now used for recreational purposes such as concerts, and the site has a restaurant and yacht moorings. During the summer, a ferry company, Spar Shipping, has five scheduled trips per day to the island, with the trip from Nyhavn taking about 40 minutes each way. There is an overnight hostel on the island too.
References:Ogrodzieniec Castle is a ruined medieval castle originally built in the 14th–15th century by the W³odkowie Sulimczycy family. Established in the early 12th century, during the reign of Boles³aw III Wrymouth, the first stronghold was razed by the Tatars in 1241. In the mid-14th century a new gothic castle was built here to accommodate the Sulimczycy family. Surrounded by three high rocks, the castle was well integrated into the area. The defensive walls were built to close the circuit formed by the rocks, and a narrow opening between two of the rocks served as an entrance.
In 1470 the castle and lands were bought by the wealthy Cracovian townsmen, Ibram and Piotr Salomon. Then, Ogrodzieniec became the property of Jan Feliks Rzeszowski, the rector of Przemy¶l and the canon of Cracow. The owners of the castle about that time were also Jan and Andrzej Rzeszowskis, and later Pilecki and Che³miñski families. In 1523 the castle was bought by Jan Boner.