Saint Nicholas' Church, Romanesque Revival church in Mesen, Belgium

Saint Nicholas' Church in Mesen is a 1928 neo-Romanesque cross-shaped church by architect Charles Patris, rebuilt after World War I. Its square light-brown and grey stone tower has paired pointed-arch louvered windows, a cross-shaped opening near the roof base, and a steep slate roof topped by a small columned lantern. A lower slate-roofed aisle adjoins the tower on the right.

Built in 1057–1060 as the abbey church of a Benedictine convent founded by Countess Adela of Flanders, daughter of King Robert II of France. She entered the convent after her husband Baldwin V's death and was buried in the 11th-century Romanesque crypt. The abbey closed in 1776 under Empress Maria Theresa; the church became Mesen's parish church and was dedicated to Saint Nicholas. Destroyed in World War I, it was rebuilt by architect Charles Patris in 1928.

The tower holds a peace carillon installed on 1 June 1986, driven by local Albert Ghekiere; it now has 59 bells, many donated by associations and countries worldwide. The PAX bell was blessed by Pope John Paul II in Ieper on 17 May 1985. Every quarter hour it plays hymns or folk music of the nations involved in the First World War.

The church is easy to reach as it sits centrally in Mesen and is clearly visible from the street. Visitors should check if it is open at certain times, particularly if interested in viewing the interior.

The tower's dome-like top earned it the nickname "Dikkop". Since 1 June 1986 it has housed a peace carillon of 59 bells, driven by local Albert Ghekiere; the PAX bell was blessed by Pope John Paul II in Ieper on 17 May 1985, and the carillon plays hymns of the WWI nations every quarter hour.