The nave had ten bays and the choir six.
Many of the bays in the harbour are largely visited on Sundays and holidays.
It was not completed, however, till the 19th century, when the west portal and towers and two bays of the nave were added, according to the plans of Violletle-Duc. The fine stained glass of the windows dates from the 13th to the 15th centuries.
With the exception of Green and Traverse bays, Lake Michigan has few indentations of the coast line, and except at the north end it is free from islands.
There are still other bays along the coast which are well adapted for commercial purposes but are used only in the coasting trade.