Geography is simply the study of the land, its features and its inhabitants - and so there are posters and pictures to create the atmosphere in a room (from classrooms for educators to bedrooms or living rooms for history buffs and knowledge hungry students) of something that was part of the past and the present.
Flags of different countries can be found altogether around an atlas of the world so you can see which country is located where, and old maps of world geography can shine light on how people used to see the world.
Maps of Africa through history can lend knowledge of how much the continent has changed and it can be done for other parts of the globe and even the entire world; international naval signals can satiate the appetite of someone who looks to the seas and oceans as posters of world globes can create the atmosphere of fascination at the world on which we live and the countries which we have defined over time.
Placing posts like these, which can range from patriotic (and so are best served in more personal spaces - or along patriotic flags of many different nations to create context and thought) to entirely educational (like current atlases of the world and old maps of the world) takes a little bit of context.
For those more personal they're best brought to personal spaces, but for those looking for an educational aid they can be placed anywhere the mind should be active and absorbing knowledge or up for potential thought.
