Bayenturm, Medieval fortified tower in Altstadt-Süd, Germany

Bayenturm is a stone tower in Cologne that was built as part of the medieval city fortifications and features sturdy walls with gun ports. The construction shows the typical design of defensive towers from the Middle Ages, with massive foundations and a strategic location along the city wall.

Built around 1220 as the southern corner tower of Cologne's eight-kilometre medieval wall, the Bayenturm was first mentioned in 1250. On 8 June 1262 the citizens stormed it, ending the archbishop's overlordship; a Cologne saying holds that whoever held the tower held the power. In 1620, during the Thirty Years' War, it was reinforced. Damaged by fire in 1697, it was restored by city architect Josef Stübben between 1895 and 1898.

Since August 1994 the tower has housed the FrauenMediaTurm, a non-profit foundation initiated by Alice Schwarzer in 1984. Its feminist archive and documentation centre covers the historical women's movement from the mid-19th century to 1933 and the new women's movement from 1971 onward. The collection holds 15,000 books, 60,000 documents such as leaflets and posters, and 33,500 articles, including every issue of Emma since 1977. The tower also contains Schwarzer's office and, since 2003, the Emma editorial team.

The tower stands on the Rhine between Bayenstraße and Agrippinawerft, about 50 metres from the present-day Rhine embankment quay. It is not open to the public as a museum; the building houses the FrauenMediaTurm foundation and the Emma editorial office, so visits are by prior arrangement only.

The tower's interior lighting comes from a skylight architect Dörte Gatermann called a "Himmelsauge" (eye of heaven), installed during the 1992 conversion, since the original openings were only narrow arrow slits. The city of Cologne funded the work with 5.5 million marks.