A wireless sensor network (WSN) is a network formed by a large number of sensor nodes, each equipped with sensor(s) to detect physical phenomena such as heat, light, temperature, pressure, motion or sound etc. This paper focuses on the historical background of how the wireless sensor network has come into the existence, it’s types, and the current trends. It also presents the applications of WSNs in various fields like agriculture, environmental monitoring, military, health, automation, industrial monitoring, public utilities, assets management and many more. This research paper has also pinpointed the various challenges and issues which are being faced in Wireless Sensor Network and the future possibilities of Wireless Sensor Network