Tucked in the shadow of mighty Sacré-Coeur is one of the oldest churches in Paris. Built in 1147 on the site of a 5th-century temple to the god Mars, this small sanctuary with its impressive sculpted metal doors was once part of a substantial Benedictine abbey. Besides the church, all that remains is a small cemetery, now closed (you can see it through the ornate metal door on the left as you enter the courtyard). Renovated multiple times through the ages, St-Pierre combines
various styles. Interior elements, such as the columns in the nave, are medieval; the facade dates to the 18th century, with renovations in the 19th century; and the impressive stained-glass windows are 20th century. Maurice Utrillo's 1914 painting of the titular saint hangs in the Musée de l'Orangerie.