When did Horizon Season 4 Episode 21 air?
Horizon Season 4 Episode 21 aired on November 21, 1967.
Horizon
Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.
Season 4 · Episode 21
The Life and Death of the Pine Processionary
Nov 21, 1967·1h
Horizon reports on the problem of exterminating the pine processionary caterpillars infestation from the pine forests of Provence, Canada.
Episode FAQ
Direct answers for episode-level questions and details.
How long is Horizon Season 4 Episode 21?
This episode runs for approximately 60 minutes.
Comments
Comments coming soon
Discuss episodes with other viewers