| 1974 | Horizon Season 1974 Episode 32 – The Lysenko Affair | | 0 | 10 years |
| Horizon Season 1974 Episode 31 – How on Earth Did They Do That? | | 0 | 10 years |
| Horizon Season 1974 Episode 30 – The Neglected Harvest | | 0 | 10 years |
| Horizon Season 1974 Episode 29 – Joey | | 0 | 10 years |
| Horizon Season 1974 Episode 28 – The Other Way | | 0 | 10 years |
| Horizon Season 1974 Episode 27 – The First Signs of Washoe | | 0 | 10 years |
| Horizon Season 1974 Episode 26 – Do as You Are Told | | 0 | 10 years |
| Horizon Season 1974 Episode 25 – An Unholy Scramble | | 0 | 10 years |
| Horizon Season 1974 Episode 24 – Adam or Eve? | | 0 | 10 years |
| Horizon Season 1974 Episode 23 – Listen and Be Loyal | | 0 | 10 years |
| Horizon Season 1974 Episode 22 – What Price Steak? | | 0 | 10 years |
| Horizon Season 1974 Episode 21 – Mines, Minerals and Men | | 0 | 10 years |
| Horizon Season 1974 Episode 20 – The Immigrant Doctors | | 0 | 10 years |
| Horizon Season 1974 Episode 19 – The Race for the Double Helix | | 0 | 10 years |
| Horizon Season 1974 Episode 18 – Hills of Promise | | 0 | 10 years |
| Horizon Season 1974 Episode 17 – Who Needs Skills? | | 0 | 10 years |
| Horizon Season 1974 Episode 16 – The Secrets of Sleep | | 0 | 10 years |
| Horizon Season 1974 Episode 15 – Search for Life | | 0 | 10 years |
| Horizon Season 1974 Episode 14 – Bridges: When It Comes to the Crunch | | 0 | 10 years |
| Horizon Season 1974 Episode 13 – A Noah’s Ark for Europe | | 0 | 10 years |
| Horizon Season 1974 Episode 12 – The Hunting of the Quark | | 0 | 10 years |
| Horizon Season 1974 Episode 11 – This Yankee Dodge Beats Mesmerism Hollow | | 0 | 10 years |
| Horizon Season 1974 Episode 10 – The First Ten Years | | 0 | 10 years |
| Horizon Season 1974 Episode 9 – Fusion: The Energy Promise | | 0 | 10 years |
| Horizon Season 1974 Episode 8 – The Future Goes Boom | | 0 | 10 years |
| Horizon Season 1974 Episode 7 – Where Did the Colorado Go? | | 0 | 10 years |
| Horizon Season 1974 Episode 6 – The Writing on the Wall | | 0 | 10 years |
| Horizon Season 1974 Episode 5 – Pedal Power | | 0 | 10 years |
| Horizon Season 1974 Episode 4 – The Great Fish Hunt | | 0 | 10 years |
| Horizon Season 1974 Episode 3 – Never Too Late to Learn | | 0 | 10 years |
| Horizon Season 1974 Episode 2 – Bird Brain – The Mystery of Bird Navigation | | 0 | 10 years |
| Horizon Season 1974 Episode 1 – A Matter of Self-Defense | | 0 | 10 years |
