The Lyttelton Rail Tunnel, initially called the Moorhouse Tunnel, links the city of Christchurch

Christchurch

Christchurch is the largest city in the South Island of New Zealand, and the country's second-largest urban area after Auckland. It lies one third of the way down the South Island's east coast, just north of Banks Peninsula which itself, since 2006, lies within the formal limits of...

 with the port of Lyttelton

Lyttelton, New Zealand

Lyttelton is a port town on the north shore of Lyttelton Harbour close to Banks Peninsula, a suburb of Christchurch on the eastern coast of the South Island of New Zealand....

 in the Canterbury region

Canterbury, New Zealand

The New Zealand region of Canterbury is mainly composed of the Canterbury Plains and the surrounding mountains. Its main city, Christchurch, hosts the main office of the Christchurch City Council, the Canterbury Regional Council - called Environment Canterbury - and the University of Canterbury.-...

 of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

’s South Island. It is the country’s oldest operational rail tunnel, and is on one of the first railway lines in the district. On completion in 1867 it became the first tunnel in the world to be taken through the side of an extinct volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

, and at 2.7 km, the longest in the country.