The talk will be a survey over various diameter 2 properties, together with some history of how it all evolved after starting just around the year 2000. How rotund diameter 2 spaces can be is a question of special interest. There are also some natural open questions that will be presented. An example of such a question goes like this: M-embedded spaces have the property that all subspaces have very strong diameter 2 properties. Can we characterize the Banach spaces where all subspaces have the diameter 2 property?