As usual, there are a couple of oops spots, but this is one of my favorite Debussy pieces, because you can follow the narrative of what's going on in the music like a story. From Wikipedia:

"This piece is based on an ancient Breton myth in which a cathedral, submerged underwater off the coast of the Island of Ys, rises up from the sea on clear mornings when the water is transparent. Sounds can be heard of priests chanting, bells chiming, and the organ playing, from across the sea. Accordingly, Debussy uses certain harmonies to allude to the plot of the legend, in the style of musical impressionism."

See if you can hear the cathedral rising up, hear the priests chanting, hear the bells ringing, and ultimately hear the Cathedral sink back into the sea.