This was the first ever manned mission which was sent to the orbit of the moon. Spacecraft left Earth's surface on 21 December with three Astronauts- Jim lovell, Frank Brman and William Anders. 

This mission was called Apollo8 and the astronauts entered the orbit at the christmas eve. These astraonauts were the first to see the Earth as a whole planet. They observed moon directly through the orbit.

This mission was to conduct the study of moon after entering the lunar orbit. This amazing mission was the devine towards the scrutiny of the activities of Earth. 

Also Read:

Where is the world's 'oldest bank' situated ?

Do you know how 'Bats' communicate?

Can you measure the amount of oxygen in inhaled air???