North American XB-70 Valkyrie

Of the many futuristic military aircraft concepts created in the 1950s the North American XB-70 still stands out as the most awe-inspiring. With its huge, white partially-folding delta wing, its fuselage resembling a striking cobra, and its extraordinary performance, it was one of the foremost technological achievements of the 20th Century.

A strategic bomber built to outrun any Soviet fighter jet, it could reach Mach 3 with a full nuclear payload--as fast as the legendary SR-71 Blackbird b...