An hour west of Melbourne, the Werribee River has carved a deep, rugged gorge through the volcanic and sedimentary rock of the state park, a surprisingly wild landscape close to the city. The Circuit Walk traces the gorge for around ten kilometres, clinging to ledges above the river, crossing scree slopes and passing deep green swimming holes at the bottom. Sections are steep and rocky - a fixed cable helps across one exposed traverse - and the walk is a favourite training ground for Melbourne bushwalkers. Wedge-tailed eagles ride the updrafts and the river pools are a welcome cool-off in summer.