The church can be visited
Mariae Himmelfahrt Church

On the western edge of Andernach, the Parish Church of St. Mary of the Assumption rises, a gallery basilica with four towers. Its location directly on the city wall dates back to Roman times when the Antunnacum fort stood here.
History+
Carolingian graves beneath the current church building attest to an early foundation. Little is known about the appearance of the first church and a successor building from the early 12th century, but the freestanding bell tower from that period is preserved. In 1194, Emperor Henry VI gifted the predecessor building to Archbishop Johann I of Trier. Just four years later, in 1198, during a conflict between Otto IV and Philip of Swabia, who conquered and plundered Andernach, the church was largely destroyed by fire. Archbishop Johann I then had the current St. Mary's Church built as a three-aisled gallery basilica by approximately 1220, integrating the old bell tower as the northeast tower. By the mid-13th century, the western towers were completed. In the early 18th century, the church was in a ruinous state. A 1739 report even suggested the demolition of towers and side aisles, but the commitment of Andernach's citizens prevented this.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Maria-Himmelfahrt1-Andernach.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: 50.4395, 7.3964