St. Paul's Cathedral Flood Gauge

Saint Paul’s Cathedral in Liège has an unusual history. Founded as a collegiate church in the 10th century and rebuilt between the 13th and 15th centuries, it was never intended to be a cathedral. That only came later, after the destruction of Saint Lambert’s Cathedral during the Revolution and its official restoration under Napoleon I, when Saint Paul’s was chosen as the city’s new seat.

Today, the cathedral houses many treasures—including the infamous Génie du Mal statue—but sharp-eyed visitors will notice something stranger: a column at the back of the nave etched with the waterlines of five floods that have entered the church since the 16th century. The Échelle de crue de Cathédrale Saint-Paul or St. Paul's Cathedral Flood Gauge.

The oldest level dates back to the flood of 1571. It is one of only three 16th-century landmarks preserved in Belgium. The highest level dates from 1643. Behind these two marks, you can see an engraved hand pointing to the level, which was a popular method of representation throughout Europe at the time. The next levels are from 1740 and the floods of December 31, 1925 and January 1st 1926. Although the preface mentions five floods, only four are visible: the fifth flood mark, from 1850, is now hidden by the base of the statue.

Some markers also include chronograms in Latin, where capital letters double as Roman numerals giving the year of the flood:

- 1571: aLto Mosa LoCo CresCens hVC appVLlt VsqVe AQUAE

- 1643: aLtIVs eXpanso fLVMIne DVXIt aqVas

- 1740: —

- 1926: CIrCUMCIsIonIs DIe hUC assUrglt aqUa

Not every flood was recorded. Before the late 1500s, Belgium kept no such markers, and lesser floods may have been dismissed as unworthy of carving into stone. The surviving “ladder of floods” (échelle de crue) is a rare and haunting reminder of the centuries when the Meuse River regularly invaded this sacred space.