But it never, ever dropped a single bomb.
With the growing realization that Soviet SAMs posed an increasing threat to American bombers, the Pentagon started to explore low-level penetration as an alternative. Low-level penetration involved flying under the radar horizon using terrain to mask a bomber’s approach, which greatly reduces enemy response times. Moreover, the development of intercontinental ballistic missiles greatly reduced the United States’ reliance on manned bombers. Many leading military strategists of the time believed bombers were too vulnerable to survive the journey into Soviet airspace. As a result, President John F. Kennedy decided to cancel the XB-70 as a frontline bomber program on March 28, 1961.
The North American XB-70 Valkyrie was the largest and fastest bomber ever built by the United States, but the massive six-engine Mach 3.0-capable jet never entered production. Only one surviving prototype sits in a museum in Dayton, Ohio, even as the Boeing B-52 it was supposed to one day replace continues to soldier on.
Recommended: 8 Million People Could Die in a War with North Korea