St. Dionysius

After Longerich was incorporated into Cologne in 1888, the old church on Kriegerplatz became too small for the growing population. In 1897 it was decided to build a larger new church west of the old one, designed by Cologne architect Franz Statz—though Wikidata's structured data also lists Vincenz Statz, albeit uncertainly. Archbishop Hubert Theophil Simar consecrated the building. On 13 March 1942 an aerial mine severely damaged the church. Reconstruction to plans by Karl Band began in the early 1960s; destroyed vaults were replaced with wooden ceilings and the interior was redesigned.

The church is laid out as a three-aisled brick basilica without a transept. The tower stands to the side, in the southwest.

Surviving from the original furnishings are a 15th-century statue of Mary and an Anna Selbdritt group, along with Baroque sculptures of the parish patron Dionysius from 1777 and terracotta figures of the Apostle James from 1776. Another figure of James with pilgrim's staff and shell came from Cologne's St. Kunibert church. Heinz Gernot created the altar with its Crucifixion group, the 1971 portals, and the 1973 ambo; the 1995 Stations of the Cross are by Franz Thaler.

Built in 1966 by the Bonn firm Johannes Klais, the organ has 22 stops, combining a mechanical key action with an electric stop action.

The stained-glass windows come from various artists, some unknown. Maria Meng designed three choir windows in 1956 depicting scenes from the Old Testament and the life of Jesus. Around 1960, windows with interlace patterns of unknown authorship were installed beside the entrance portal. Josef Henseler created three windows in 1970: an ornamental composition in the organ loft and two free compositions in the choir. In the choir chapel, two 1991 windows based on designs by Dieter Hartmann depict invocations from the Litany of Loreto; two further windows by Karl-Josef Schneider from around 1992 show the churches of St. Dionysius in Longerich and in Saint-Denis.