Trekroner Fort

The original location of Trekroner Fort was a few hundred meters north of the current one.

The fort was an important part of the Danish line of defense during the Battle of Copenhagen in 1801.

From 1818 to 1828 and in 1860, the fort was strongly enhanced, but its military significance diminished after the First World War.

Trekroner Fort is one of three artificial islands that were created to defend the entrance to Copenhagen's harbor (the other two are Middelgrundsfortet and Flakfortet).

Trekroner is seen, as a ferry with Hallandsen onboard passes by, at 0:31:20 in the 1977 Olsen-banden film The Olsen Gang Outta Sight.