The South Western most point of Rottnest Island, geographically the furthest point from the Thompson Bay settlement, which makes it a healthy 11km bicycle ride for those keen to see it.
Though technically the West End is a large section of the far side of the Island, you cannot truly say you've made the journey until you reach Cape Vlamingh (named for the Dutch explorer who explored much of the Island). The Cape is a cliff-face promontory, looking out onto a stretch of reef that adjoins the Island and stretches out for hundreds of meters.
The view from West End is truly spectacular, though you will have to decide for yourself if it is worth the cycle to get there.
Whales and dolphins are often spotted frolicking off the coast, and there are a large variety of native birds that make this coast their home -- making it a favourite stop for school camps. As the half-way point in any circumnavigation of the island, it also marks the start of the 'race home' during any school camp, where the camping students race each other back to Thompson Bay for bragging rights.
Being well outside the settlements there is no fresh water available so be sure to bring it with you -- though these days the enterprising General Store sends a man on a trike to sell refreshment of dubious sugar content to those who have made the journey.
For those of a less energetic disposition, the Rottnest Bus makes a stop at the Cape, though this is definitely considered the soft option, and well win you no respect from the locals.