Eglise Saint Germain des Prés was originally the church of a Benedictine abbey founded in the 6th century. It was destroyed by the Vikings and was rebuilt around the year 1000, in a Romanesque style. It is considered the oldest existing church in Paris. To discover more, why. not join a guided tour of the church run by volunteers or attend a free organ concert (last Sunday of each month at 3.30pm): details are here.