Located within the Arthurs Pass National Park, the major national park in the center of the South Island New Zealand, the old Arthurs Pass road is known as the zigzag. It was built across a huge scree slope and was subject to erosion due to earthquakes and flooding. In the last century the road was cut further and further back into the hillside, until it was 20 metres higher and 65 metres further back into the slope than it had been seventy years earlier.
The zigzag was a notorious stretch of road that went through the middle of a scree that was constantly moving. Rockfalls and screes were a hazard for road construction and maintenance for more than 100 years. This amazing drive offered an amazing scenery. Located in an active seismic region, the infamous section of Highway 73 demanded first gear for most motor vehicles. This road was always a challenge due to the huge shingle slides coming off the mountains and tight corners. They had to keep replacing this road as it was moving down the mountain. Sections of the highway were progressively moved uphill across an old landslide path creating the Zig Zag. Eventually it became infeasible to maintain the highway due to the increased risk that another large landslide would permanently close the highway. This very windy section was replaced by a viaduct through the middle of the Ōtira gorge in 2001, beneath the zig-zag.