Cologne

Twenty-five stops in three layers: Roman Cologne with the Colonia Claudia Ara Agrippinensium and the Romano-Germanic Museum; the ring of Romanesque churches – St. Gereon, St. Maria im Kapitol, Groß St. Martin, St. Pantaleon, St. Aposteln; and then the cathedral, the Wallraf-Richartz Museum, the Museum Ludwig, the Hohenzollern Bridge and the DITIB central mosque.

Much of the cathedral is younger than the town hall next door. The foundation stone was laid on 15 August 1248, work stopped in 1528, resumed in 1823 and finished on 15 October 1880 – the towers, the nave and the façades are nineteenth-century work. At 157.2 metres it was then the tallest structure in the world for four years. Fourteen high-explosive bombs hit it during the war; it stayed up.

On 3 March 2009, shortly before 2 p.m., the historical city archive collapsed when groundwater pushed through a faulty diaphragm wall on the underground railway site; two people died, and of 30 shelf-kilometres about 95 per cent had been recovered by 2011. The new archive at Eifelwall opened on 3 September 2021. St. Gereon's decagon of 1219–27 encloses a late-antique oval building from around 350; its restoration was only completed in 1985. And opposite the Jülichsplatz, Farina has been making eau de Cologne since 13 July 1709, with a fragrance museum since 2003.