Explore New York in Google Street View

New York is two cities and the border is 14th Street. Above it the 1811 Commissioners' Plan imposed a numbered grid on farmland, twelve avenues by one hundred and fifty five streets, and it was followed almost to the letter. Below it the streets predate the plan and follow old paths, property lines and the shoreline, which is why Greenwich Village has a West 4th Street crossing West 11th. Switch to satellite and the join is one of the clearest urban boundaries on the planet.

The grid is what makes Manhattan so good to explore virtually. Every avenue runs the full length of the island and is photographed continuously, so you can follow Fifth Avenue from Washington Square to Harlem in one direction of travel. Twice a year the setting sun lines up exactly with the cross-streets, an effect somebody named Manhattanhenge, and it only happens because the grid is rotated twenty nine degrees off true north.

Times Square is the obvious stop and it is worth understanding what you are looking at. The zoning there legally requires buildings to carry illuminated signage of a minimum size, which is why the advertising is not decoration but a planning obligation. It is the only place in the country where a landlord can be compelled to put up a screen.

For the version of the city people live in, cross the river. Brooklyn's brownstone neighbourhoods, Park Slope, Fort Greene, Bedford-Stuyvesant, are rows of nineteenth-century terraces with stoops, and the streets are lined with trees in a way Manhattan mostly is not. DUMBO is the photograph everybody takes, framing the Manhattan Bridge between two warehouse walls, and the exact spot is on Washington Street.

The High Line is the best walk in the imagery. It is a freight railway thirty feet above the street, closed in 1980 and reopened as a linear park in 2009, and it was captured on foot for its full length. Walking it virtually gives you something no road-level camera can: the view into the second floor of buildings, the gaps between blocks, and the Hudson appearing at the cross-streets.

One quirk. Manhattan's avenues were photographed at different times, so you can move one block sideways and land in a different season. It is not a fault, and once you notice the light changing at the corners it becomes a small game of working out which pass you are on.