Do you know this Gustav Mahler work?

Years ago (10 or 12), I bought a cette tape of Gustav Mahler. The cover was very colorful - almost a stained gl look, if my memory serves me correctly. The trouble is, I cannot for the life of me remember the name of the work. I thought there was the word "nacht" in it, but looking online, I don't find the right one. All I remember is how beautiful and uplifting it was (though there were some dark areas, too). Does anyone have this cette and if so, can you tell me the name of it?