The island's name is a misreading. In 1696 the Dutch navigator Willem de Vlamingh recorded a landmass overrun by what he took to be large rats, and set down "Rottenest" — rat's nest — in his log. The animals were quokkas, small marsupials found almost nowhere else. The Whadjuk Noongar people had known the place for far longer as Wadjemup, meaning "place across the water", a name that acknowledges the sea rise which severed the island from the mainland roughly seven thousand years ago. That separation explains most of what a rottnest island guided bus tour passes today. Isolation preserved a landscape the mainland lost: sixty-three beaches, twenty bays, hypersaline lakes stained pink by algae, and limestone reefs that have wrecked more than a dozen ships. It also produced an ecology without foxes or cats, which is why the quokka population — estimated between eight and twelve thousand — survives at a density found nowhere else in Australia. The built history is heavier. Between 1838 and 1931 the island operated as a penal establishment for Aboriginal men and boys from across Western Australia; roughly four thousand were imprisoned in the Quod, the octagonal cell block still standing near Thomson Bay, and at least 373 died there. The site is now formally recognised as a burial ground, and interpretation on Wadjemup island tours has shifted considerably to reflect that. Later layers sit on top: the Oliver Hill Battery, completed in 1937, still carries its two 9.2-inch guns and a network of tunnels; Bathurst and Wadjemup lighthouses, built in 1900 and rebuilt in 1896 respectively, mark the island's two navigational extremes. Architecturally, the island reads as a compressed record of colonial Western Australia. Thomson Bay's settlement retains 1840s limestone cottages, a hay store, a boys' reformatory and a governor's summer residence, most quarried from the island's own stone. Vlamingh Lookout, at 45 metres, is the highest point and offers the clearest read of the geography: salt lakes to the west, the settlement to the east, the mainland a low grey line beyond. Wadjemup was declared an A-Class reserve in 1917. Cars remain effectively banned, which is why a coach tour of the island — and cycling — became the practical means of covering its eleven-kilometre length. A rottnest island guided bus tour tour therefore does something a private vehicle never could here: it narrates the ground while crossing it, linking prison, battery, lighthouse and lake into a single sequence.