Baldwin Street, located in southern New Zealand in North East Valley, a northeastern suburb of Dunedin, is famous for being the steepest street in the world. Its original listing in the "Guinness Book of World Records" that claimed a 38 degree maximum slope was based upon an error, either typographical or a mix-up between grade measurement by degree or percentage. However, Guinness still recognizes the street as the world's steepest with the correct measurement, a 35% maximum gradient.

A visitor traveling up Baldwin Street from its lower, eastern end would experience only a moderate climb along an asphalt surfaced road. But the straight, short street's upper end, paved with concrete, because asphalt would melt in warmer weather and slide downhill, slopes upward at 19 degrees (or by 35%), presenting a much more rigorous climb.

At first glance, the street seems to be a cul-de-sac at first glance, it is linked by a footpath named Buchanan Street to adjoining streets, Arnold Street and Calder Avenue. This street's extra-steep slope happened by accident because late 19th Century designer Charles Kettle, like other planners of New Zealand's cities working in London offices, took no account of terrain features and laid out Dunedin's streets along a grid. As a result, neighboring streets running parallel are steeper than average too.

During the "Baldwin Street Gutbuster" sports event, held every summer since 1988, athletes run from the bottom to the top and back down again. Sponsored tennis balls and candies are rolled down the street to raise money for charities in two other annual events.

Riding or careening down the steepest street in the world remains a dangerous, yet irresistible, challenge for some daredevils and revelers. A college student lost her life in 2001 while attempting to roll down in a wheelie bin, but stuntman Ian Soanes succeeded in motorcycling down on one wheel in 2010.