In 1987, P. Bak, C. Tang and K. Wiesenfeld (BTW) proposed the concept of self-organised criticality (SOC) to explain the occurrence of 1/f noise detected for transport in various systems. Since then, SOC has provided a possible framework explaining how chaotic systems can emerge from simple rules in nature without fine-tuning of parameters. As an example of this concept, we examine the Sandpile model, also introduced by BTW. Besides some of the basic properties, we focus on the proof of the existence of the weak limit of the equilibrium measure in the thermodynamic limit, its consequences and some open questions of the model.