" Basilica of Notre-Dame, Boulogne"

The basilica, a prominent landmark of the city with its 331 ft high dome,  was built between 1827 and 1875 on the site of the medieval cathedral of Boulogne: the basilica is still known locally as the "cathedral", although the present church has never had that status. 

Notre-Dame was built to a new design inspired by both Classical and Renaissance styles, and bears many similarities to St Paul's Cathedral. The area beneath the dome was initially designed to form the complete church, but additional funding allowed the expansion to the nave and transept that form a Latin cross. This gives the finished building the unusual internal appearance of being formed by two distinct churches, each of which is equally beautiful.