The inherent curiosity of man never lets him rest. More than 50 years ago, when in 1961 Yuri Gagarin from U.S.S.R became the first man to enter into space; human potential took a great leap forward. Ever since that day, mankind has never looked back. We have achieved a significant number of milestones in the field of space exploration and given below is the list top 10 achievements. Take a look.