Chapel Madonna in the Green

As early as the 13th century, a church dedicated to Saint Stephen stood on this spot. Declared structurally unsound, it was demolished in 1860 and replaced by a successor building in 1862. This second Stephanus church served the entire Mauenheim parish until the 1930s, before being destroyed in the Second World War.

After the war, entrepreneur Thomas Carl Tromm expanded his wax raw-material factories in Weidenpesch. Grateful that his family and business had survived the war unscathed, he made a gift to the parish. Encouraged by his friend, parish priest Fürtjes, he had a Marian chapel built on the site of the destroyed Stephanus church; the designs were provided by his son, Carl Tromm.

The east-facing hall church ends in a straight choir; rectangular transverse bays adjoin the hexagon's long sides to the west and east. The bell in the ridge turret was cast by master bell-founder Engelbert Gebhard of Kempten in the Allgäu.

To mark the 100th anniversary of the dogma of the Immaculate Conception and the 40th anniversary of the apparition at Fátima, Cardinal Frings commissioned a crowned Madonna figure with the Christ child and a billowing cloak, carved from oak. During the Marian Year of 1954 it was carried through Cologne's parishes. On 8 December 1954, the Feast of the Immaculate Conception and the cathedral's high feast day, the figure was brought into Cologne Cathedral, and a few months after the chapel's consecration it was installed there.

The stained-glass windows, doors, interior grilles, tabernacle, and candleholders were made by master locksmith Hloch. The 1954 cathedral-glass windows, featuring ornamental cross motifs, are works by Thomas Carl Tromm modeled on the window design of the Heilig Kreuz church. The images depicting the life of Jesus came from Bavaria and were donated by Farbwerke Hoechst. The figures of the Madonna, Saint Stephen, and the Apostle Thomas were designed and carved in Kevelaer.

After completion, the chapel hosted Marian devotions, weddings, anniversaries, and baptisms. Following repeated break-ins and damage, it is no longer regularly open to the public.