The Saint-Sulpice church, located a few blocks south of the Saint-Germain-des-Prés church, is the second-largest church in Paris, after Notre-Dame. It was completed in the 17th Century and was built on the site of a 13th-Century Romanesque church. In the square in front of the church, the Place Saint-Sulpice, there is a large fountain called the Fountain of the Four Bishops, which was designed by Joachim Visconti and completed in 1848.

The church has two mismatched towers at its front corners. Apparently there were plans to make them match that never quite happened. During our visit there was a crane and a fair amount of scaffolding, but they seemed to be there for maintenance and restoration work.

Inside the church were the usual church things – a main altar, several side chapels (some with tombs), a pulpit, stained glass and an organ. But the organ is anything but usual, being one of the largest in the world. It was built in 1862 by Aristide Cavaillé-Coll, partly with pieces from the previous organ. Nobody was playing it during our visit, but it was still impressive to look at.






One unusual feature in the church which we failed to notice at the time was something called a gnomon, which at Saint-Sulpice is a long brass line embedded in the floor in the transept, extending from a plaque near the south end to an obelisk at the north end. This is mentioned in Dan Brown's book The da Vinci Code, and is mistakenly said to have represented a Parisian "prime meridian" (or "Rose Line") at one time. While the line does extend north-to-south and there was such a thing as a Parisian meridian, it was located in the nearby Paris Observatory. The line in Saint-Sulpice was used to measure certain astronomical events, but this was initially because of the religious significance of some of them. The gnomon worked (and continues to work) along with a small hole in one of the stained glass windows, which projects a bright spot of sunlight on the floor during the day. At "true noon" each day the spot crosses the brass line, and throughout the year the spot travels north and south along the line when observed at noon each day. When the spot is on the plaque, the summer solstice is taking place, and when it's on the top of the obelisk (necessary because there wasn't enough floor at the north end; they could've marked a spot on the wall, but an obelisk was cooler), it's the time of the winter solstice. Halfway along the line is a mark representing where the spot will be at the vernal and autumnal equinoxes.

Oblivious to all of this, we walked around and took our pictures, and eventually exited the church to go a few more blocks southward to our next destination, the Luxembourg Gardens.