IoT (Internet of Things) one of the most exiting trends and innovation in the recent history of technological advancement. Also the advances in computer hardware, embedded system devices, networking devices, display devices, control devices, software enhancements etc. has tremendously supported IoT to grow slowly and steadily from leaps to bounds. With computation, connectivity, and data storage becoming more advanced and universal there has been an explosion of IoT based application solutions in diversified domains from health care to public safety, from assembly line scheduling to manufacturing and various other technological domains. IoT can be defined as a network of physical objects, devices that contain embedded technology (like intelligent sensors, controllers etc.) whichcan communicate, sense, or interact with internal or external systems. In other words, when objects can sense and communicate, it changes how and where decisions are made, and who makes them and accordingly operations can be carried out. In this survey a conscious effort has been put forward to investigate the state of the art involved in IoT and its various diversified engineering applications. Latest trends & evolution, challenges, and future scope of this technology have been touched upon for better understanding. Various IoT based applications have been explored and possible approach for enhancing the use of this technology have been discussed in this paper. Future directions and suggestions for effectively and efficiently improving the IoT based application areas have been touched upon. This paper will provide a better insight for anyone who wishes to carry out research in the field of IoT. In this paper we have tried to provide a holistic perspective on IoT and IoT based applications, application areas, research challenges in IoT, trends and future possibilities in IoT.