Albert Park tunnels

The Albert Park tunnels are found largely beneath Albert Park, in central Auckland, New Zealand. The tunnels were constructed as air raid shelters during the Second World War. At the conclusion of the war they were sealed to prevent vandalism or misuse by the public, and as a protection against carbon dioxide build-up or tunnel collapse.

New Zealand's involvement in the war began in 1939, and with Axis naval activity occurring in New Zealand waters, domestic defence plans were necessary, with much capital being invested. Matters became urgent with the entry of Japan into the war in 1941.

A number of coastal defences were already in place throughout the country, with a concentration in Auckland, and Auckland City Council felt the need for air raid shelters in the central city, in preparation for Japanese attack. Work began in December 1941, and by January 1942, 16,300 feet of slit trenches had been dug around the city. Additional shelters were created in basements, the Domain, Grafton Gully, and the old Parnell railway tunnel.

Auckland city centre had a daytime population of 70,000, but by April 1942 shelter capacity was only 20,000. Furthermore, experience in Britain during the Blitz indicated that deep shelters provided greater protection. Due to its topography and central location, Albert Park – a communal facility built in the 1880s on the site of an 1840s army barracks – was chosen as the site for a major construction. In 1942 a large complex of tunnels and shelters was established under the park, capable of sheltering 20,400 people.

The tunnels were designed by city engineer James Tyler, and were estimated to cost £120,000 (about £6 per head), with £90,000 of the cost met by the government and the rest by Auckland City. With planned shifts running twenty-four hours, the work was expected to take four to six months. Work began in February, with up to 300 men in gangs working three shifts a day six days a week, and the digging was completed in August. Carpentry and plumbing, at additional cost, was added over the following two months. The tunnels were officially opened by Mayor John Allum in October 1942.

There are more than 3.5 kilometres (2.2 mi) of tunnels, reaching from Constitution Hill to Wellesley Street, involving a network of shelters, sanitation facilities and first aid posts, all ventilated by air shafts, with a total of nine entrances. The tunnels run through sandstone and volcanic rock, and were mainly dug by hand by a team of 114 council workers, most of whom were middle-aged men who were unfit for war. The tunnels were lined with over 975 km of New Zealand native timber, including Kauri, Heart Rimu, Larch and New Zealand Stringy Bark. A total of 315 people were involved with this project.

The central, arched access tunnels were 9 ft high (2.7 m), 15 ft wide (4.6 m), and 3,700 ft long (1,100 m); the grid of accommodation galleries – totalling 6,000 ft (1,800 m) – were 7 ft (2.1 m) square and provided with wooden seating. The floors were covered with scoria.

The tunnel complex, unlike many other air raid shelter complexes, does not have blast doors, but instead has baffles. The baffle is a block in a tunnel constructed from wood, lead and stone to absorb the shock wave in the event of a bomb blast. The small tunnels around them allowed passage and reduced the shock with the perpendicular reflections.^{[citation needed]}