What happened between sputnik and Apollo?

The US Apollo projects were geared toward landing man on the moon. They lasted

from 1963 to 1972, with six successful moon landings from '69 to '72.

The Russian Sputnik went up in 1957.

Both countries were involved in the competitive "Space Race" during those years.

Eventually, in 1975, the co-operative Apollo-Soyuz Test Project human spaceflight

mission occurred.