I love the neuroethology interpretation of word Umwelt, which is the unique way different animals sense a slice of multi-sensory world we live in. From this view, the umwelt of humans, which is primarily visual is very different from that of echolocating bats, which is primarily audition. But it is not just the primary sensory modality - the way they perceive the world is completely different - the smells they are attracted to, the tastes they prefer, the flow of air on their body and their perception of movement.
I find the idea of Umwelt very cool. In extension, I feel that the way every human perceives the world is slightly different, contingent on their culture, their interests etc.