In the first two lectures, I will give an elementary introduction to tropical geometry, focusing on the combinatorial aspect. I will not assume any prior knowledge of algebraic, polyhedral, or tropical geometry, and I will try to make these lectures accessible to people with a broad range of backgrounds. The third lecture will be devoted to applications of tropical geometry both inside and outside mathematics; For example, I will describe some of the applications in toric geometry, and also in phylogenetic tree space and tropical data science.