July 17, 1975 – Apollo – Soyuz dock

On July 17, 1975, an Apollo spaceship docked with a Soyuz spacecraft in orbit in the first superpower linkup of its kind.

The Soyuz was launched just over seven hours prior to the launch of the Apollo CSM. Apollo then maneuvered to rendezvous and docking 52 hours after the Soyuz launch. The Apollo and Soyuz crews conducted a variety of experiments over a two-day period. After separation, Apollo remained in space an additional 06 days. Soyuz returned to Earth approximately 30 hours after separation.

http://history.nasa.gov/apollo/apsoyhist.html