The bridge over Auckland Harbour celebrates its half century this year, and it has been given a major upgrade to ensure that safety is maintained in New Zealand's largest city. Mary Searle reports. Auckland is New Zealand's largest city, home to nearly a third of the entire country's population. It's a sprawling metropolis, and its 1.3 million people are spread over 637km² of city, suburbs and islands. The Auckland Harbour Bridge, which celebrates its 50th birthday in May, is a vital link in the city's road