Ten favorite unit studies from the archives: 1. Free Nature Studies: Our Wonderful World 2. The Horse 3. The Oregon Trail 4. The Iditarod: A Unit Study 5. Winnie-the-Pooh 6. Around the World in 80 Days: A Unit Study 7. Dickens A Christmas Carol: A Unit Study 8. The Transcontinental Railroad 9. The Oklahoma Land Rush: A Unit Study 10. Johann Sebastian Bach: A Unit Study Ready for More? View all of our free unit studies and book studies! You can also browse our free units by date, in chronological order , or by subject.