Breathtaking in the richness of its interior furnishings and big enough to hold 4,000 worshipers, this magnificent structure was designed in 1824 by James O’Donnell, an Irish-American Protestant architect from New York—who was so profoundly moved by the experience that he converted to Catholicism after its completion. The impact is understandable. Of Montréal’s hundreds of churches, Notre-Dame’s interior is the most stunning, with a wealth of exquisite details, most of it carved from rare woods that have been delicately gilded and painted. O’Donnell, clearly a proponent of the Gothic Revival style, is the only person honored by burial in the crypt. The main altar was carved from linden wood, the work of Québécois architect Victor Bourgeau. Behind it is the Chapelle Sacré-Coeur (Sacred Heart Chapel), much of which was destroyed by an arsonist in 1978; it was rebuilt and rededicated in 1982. The altar displays 32 bronze panels representing birth, life, and death, cast by Montréal artist Charles Daudelin. A 10-bell carillon resides in the east tower, while the west tower contains a single massive bell, nicknamed “Le Gros Bourdon,” which weighs more than 12 tons and emanates a low, resonant rumble that vibrates right up through your feet. A 35-minute sound-and-light show called “Et la lumière fut” (“And Then There Was Light”) is presented Tuesday through Saturday evenings from the last week in June through the first week of January, but not on holidays. Legendary tenor Luciano Pavarotti performed his famous Christmas concert here in 1978, and French-Canadian songstress Céline Dion had her Cinderella wedding here in 1994.