This deep gorge has a complex history of formation.

The Pillars of Hercules: The river has eroded a narrow channel through ancient lava flows (350,000 years and older) of andesite and ignimbrite rock. You can view the spectacular ravine from a 40 m long suspension bridge, which you can reach via the walking track, or alternatively from the car park 2 km along Kaimanawa Road.

To get to hidden viewing spot: From carpark take the track to the left of the bridge. After 5min you'll see a very wide tree on the left and a partially formed track heading off to the right. The track is easy to follow for a few mins to reach the viewpoint. From here you can continue another 10mins down to river.

Must have decent grip shoes and be able to follow unformed trail. Very steep in places but with roots to hold. No easy bank on river, so would have to wade across to get to water hole. We recommend crossing where track comes out or nearby if wanting to get to other side of river.

If you have time, we recommend an extra walk:

https://www.alltrails.com/trail/new-zealand/waikato/pillars-of-hercules

https://www.alltrails.com/trail/new-zealand/waikato/urchin-campsite-to-pillars-of-hercules

Urchin Campsite to Pillars of Hercules: https://www.doc.govt.nz/parks-and-recreation/places-to-go/central-north-island/places/kaimanawa-forest-park/things-to-do/tracks/urchin-campsite-topillars-of-hercules/