Cedergrenska Tornet is an eccentric early 20th-century tower in Stocksund, north of central Stockholm. It was begun in 1908 for the telephone entrepreneur Albert Gotthard Nestor Cedergren, left unfinished for decades, and finally completed in the 1990s.
The tower is now used for events, so access can be limited, but the building and surrounding park make a good short detour if you are exploring the northern suburbs. It is about a kilometre from Stocksund station on Roslagsbanan.