Almost 100% of Negombo's population is Roman Catholic. As such you will find so many churches scattered across the town. The largest cathedral, which is incidentally also, the largest cathedral in Sri Lanka is St. Mary's Church, Negombo. The architecture is spectacular and will hold you in awe. It gets a lot of local and foreign visitors daily. The church is also home to some beautiful paintings. If you'd like to know more, you can always talk to the locals or hire a guide.