A parish church since 1288, St Catherine's, has no transept. It is a fine vessel of stone, sailing under three equal naves that put it in the family of Flemish hallekerques. The powerful square tower, erected in 1504, houses the oldest bell in Lille, "Marie" It was on the top of this tower that Chappe installed his optical telegraph in 1795. It was used as a look-out point for fires until 1891. From 1622 to 1765, there was a "reclusoir" on the north wall, a collection of miserable cells where pious people could isolate themselves. Under the pine-panelled ceiling are wood-carvings, pictures and sculptures that are well worth seeing. So are the organ, dating from 1687, and the 18th century sculpted pulpit.