And don’t rely on sat navs – look at a map too. They can take you the longest way round or get you lost, making your journey more complicated and expensive.

Within weeks of its launch, tens of thousands of Indians have filled in details of their cities, towns and villages, many of them previously blank spaces in even the most up-to-date atlases. The technology, which is being extended to other “information-deficient” regions, such as Africa, is widely viewed as the future of map-making and is on course to be worth billions for Google in advertising revenues.

Giuliani spoke to a large group of employees and later answered questions from the media in a conference room with a live picture of Earth projected on a wall screen from an AGI satellite 64,000 kilometers in space. Unlike Google Earth, which projects pictures that could have been taken years ago, this was in real time.

With the flick of a mouse, a camera zoomed in on New York City until the former mayor recognized his house.