Poland Goes Luna "16"

On November 20th 1970 Poland issued a sheet of 8, 2.50 zloty, stamps to commemorate the Russian Luna 16 unmanned moon mission.

Luna 16 was the first robotic probe to land and return from the moon with a lunar soil sample.  It was the third mission overall to return samples (The first were Apollo 11 and 12) to Earth and the first for the Russian Space Program.