You should look up a brief history of 'classical' music, because what is colloquially termed 'classical' includes a broad range of eras and styles. Mozart is true classical music (later, as opposed to Bach who pretty much started classical music, as opposed to early and Renaissance music, although it is really more of gradual shift). Beethoven on the other hand, the latest of the big three, is a Romantic composer. I think the best way to describe the difference is that Romantic pieces are 'showier.' Romanticism developed into various styles and substyles, which has continued to today. If you want a good guide to the technical aspects, Aaron Copeland wrote a book titled How to Listen to Music. Included is one of the best guides to the essential pieces. Here's a list of my personal recommendations as they come to mind: 1. Aaron Copeland -Appalachian Spring 2. Aaron Copeland- Lincoln Portrait 3. Dvorak-Symphony From the New World 4. Leonard Bernstein-Candid (whole opera, hilarious. On a side note, watch him conduct it. He doesn't really conduct, he just stands on the podium and dances. He's a genius.) 5. Shostakovich-Leningrad Symphony 6. Stravinsky- Firebird 7. Stravinsky-Rite of Spring 8. Mussorgsky-Pictures at an Exhibition 9. Handel-Water Music 10. Holst-The Planets 11. Vivaldi-The Seasons 12. Mussorgsky-Night on Bald Mountain 13. Gershwin-Symphony in Blue 14. Beethoven-Moonlight Sonata 15. Ives-Variations on America 16. Grieg-Peer Gynt 17. Sibelius-Finlandia 18. Tchaikovsky-1812 Overture (preferably with cannons) 19. Tchaikovsky-Swan Lake 20. Tchaikovsky-Sleeping Beauty 21. Tchaikovsky-The Nutcracker 22. Tchaikovsky-Symphony No. 6 23. Wagner- Entire Ring Cycle 24. Wagner-Siegfried Idyll 25. Schubert-Unfinished Symphony 26. Handel-Messiah 27. Stravinsky-Mass 28. Mozart-Requiem 29. Haydn-Symphony No. 94 (not a typo, he wrote a ton) 30. Debussy-Syrinx 31. Debussy-Claire de Lund 32. Debussy-La Mer 33. William Schuman-New England Triptych 34. All of Sousa's marches 35. Dukas-The Sorcerer's Apprentice 36. Strauss-Waltz Danube 37. Strauss-Also Sprach Zarathustra I run out of steam there. The problem with remembering the amazing pieces is that they may have number names, and then it's just not going to happen for me. Obviously, I have a bias. Syrinx is only on there because I play flute. Russians are e extremely over-represented. I don't love the Big Three, and I detest Chopin, so they're pretty absent. But, hopefully based on some of these, you can find what you like. Given more time, I could triple this list pretty easily, but it's late, and bed is calling. Enjoy!