Uluru - Ayers Rock.

Uluru is 348mts (1,142feet) high and is 9.4kms (5.8miles) in circumference.
Like the Kata Tjuta - The Olgas which are nearby, you don't realise how big it is until you see it in person.
In comparison, the Eiffel Tower is 324mts high.
Most of the rock is underground and standing on its end and it is thought that maybe as much as 5kms may be underground!