Gothic clical music?

Something like Mozart's Lacrimosa, Saint-Saen's Agnus Dei, Chopin's Nocturne In C-sharp Minor, or just any clical piece that has a very dark feeling to it. In other words, I don't want it to be "beautifully dark" like Beethoven's Moonlight Sonata or Bach's Toccata and Fugue, I want it to be beautiful in a somewhat more sinister way, if you know what I mean.