The Hoddle Grid is the layout of the streets and lanes in Melbourne’s Central Business District. It’s a fantastic example of grid-based design:

All major streets are one and half chains (99 ft or 30 m) in width, while all blocks are exactly 10 chains square (10 acres, 201 m × 201 m).

Each 10 acre block [the area between streets and including one 0.5-chain-wide lane] is divided into 20 allotments, each 0.25 square chains in area – 8 corner allotments on each street and lane corner, and 12 more allotments running between the lane and each North-South bounding street. The 8 corner allotments are square, and the other 12 allotments are oblong, but all are equal in area.

It was designed in March 1837 by Robert Hoddle and is the area bound by Spring Street and Spencer Street [at the East and West ends] and Londsdale Street/The Queen Victoria Market and Flinders Street [at the North and South ends].