(in English: Blue Tower) was a tower at the royal Danish palace of Copenhagen Castle in Copenhagen, Denmark. The tower was used as a prison and has been known as such in history. It existed from the 15th-century until 1731.

Blåtårn in 1632Edit

After Christian IV learned that his American prisoner, Eddie Cantrell, fabricated his "secret agent" circumlocutions, he angrily punished him for his deceits and sentenced Cantrell to be imprisoned in Blåtårn. When the USE Navy threatened Copenhagen and demanded surrender from a stubborn Christian, Admiral John Simpson decided to bombard the Blåtårn, not knowing that Cantrell was imprisoned there. Luckily, Cantrell escaped through the intervention of Christian's daughter Anne Cathrine before the Blue Tower was destroyed.