This photograph is one of a series made by Charles Wildbore showing the construction of the Mangahao hydro-electric power scheme in the Tararua ranges east of Shannon. This view shows the bypass tunnel above the lower dam. The light suspension bridge near the construction camp can be seen in the background. The Mangahao Power Station provides hydroelectric power and is situated near the town of Shannon. It serves Wellington, Horowhenua, Taranaki, Hawkes Bay, and the Wairarapa. After being delayed by the first world war construction began in late 1919 and the station opened in November 1924.