The church can be visited
Sankt Emmeran Church
The Catholic parish church of Sankt Emmeran in Mainz, first documented in the 13th century, was founded in the 8th century. The patronage of Saint Emmeran of Regensburg indicates an early Carolingian origin, situated along a former Roman main road.
History+
The church's origins date back to the 8th century, with its first written mention as “St. Heimerammi” appearing in 1220. While no pre-Romanesque structures remain above ground today, the five-story Romanesque main tower from the late 12th century indicates an early construction phase. Around 1300, the previous building was replaced by a simple, three-aisled Gothic basilica, which incorporated the Romanesque tower.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:EmmeranMainzChor%2BTurm2.JPG
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 50.0002, 8.2683