Napoleon wanted Mainz to have a grand theatre. The foundation stone was laid in spring 1809, but events stopped the project. Twenty years later, the city council commissioned it again, and the Grand Ducal National Theatre opened on this square in 1833.

Its outer wall curves to match the half-circle auditorium, which was reportedly a first, since theatres had always been square boxes. Bombs hit it in 1942, and it reopened in 1949. Across the square, Gutenberg’s statue looks on. Two golden lines in the pavement mark the 50th parallel, though they are a few metres off.

Both VoiceMap tours of Mainz cross Gutenbergplatz. They explain Napoleon’s theatre, point out the curved wall and the golden lines, and, in one, mark the halfway point with a café break.