Massive MIMO is most fundamental and the basis of 5G. Whole evolution from older generation to 5G in context of data speed, huge amount of data traffic handling capacity, decrease in response time, providing very large range of bandwidth, increase in coverage are, high energy efficiency and many others has been done due to this new technology called Massive MIMO. It is the basic building block for 5G, whole 5G is built upon Massive MIMO. Objectives: This paper presents the basic working of 5G networks in terms of Massive MIMO and tries to find answer of question like how it increases the capacity of data handling by a huge amount as much as 1000 times more, how it gives such high speeds, what are the concept behind this significant improvements, will there be significant increase in size of BS since massive number of antennas are used. There is also a comprehensive and statistical analysis has been done on Spectral Efficiency and Energy Efficiency giving solid evidence for the improvement in 5G networks. Analysis on various digital signal processing done in Massive MIMO and comparing various processing techniques in terms of complexity and performance. The sole purpose of this paper is to provide the basic understanding on how is 5G networks are actually working and the reason behind there improvements. Brief information is added about the projects running worldwide on Massive-MIMO and its application in future communication systems of next generation. Findings: It has been observed that to provide the performance to such high standards, massive amount of antennas are used at BS to execute a directed beams focused towards users. The size of BS remains same as it was in 4G. There is no significant increase in the size of BS it just that number of transceiver chains increases by the same amount as number of antennas per BS.