The United States cancels thier neutron bomb program (would destroy life but leave property intact) (2h 20min, apr 1, 1978 y – 20h 52min, apr 30, 1978 y)
Added to timeline:
Date:
2h 20min, apr 1, 1978 y
20h 52min, apr 30, 1978 y
~ 29 days