Ears

Ears are complicated structures, most of which is hidden inside the head, and is concerned with not only hearing but also balance. The outer ear's job is to collect sound and protect the sensitive ear drum, which is found at the bottom of the ear canal and which can sometimes cause problems by producing too much ear wax.  This may need cleaning with special drops or fluid, but never by poking anything down the ear canal, as this can easily make matters worse and cause damage. Internally, the balance mechanism tells you which way up you are, but this can become overwhelmed in travel sickness.