One easily underappreciated feature of a city street or square is its "future-proof" nature. The ancient medieval squares in places like Marrakesh and Siena are still places where stuff is sold every day, even if the stuff itself has changed over the last five hundred years. The city square is a fairly future-proof technology, as is the shopping street, even in an age of online shopping. For example, the same physical store that once sold buggy whips and typewriters might now repair damaged phones and sell bubble tea. The same infrastructure supports evolving uses. Jane Jacobs, the great prophet of the city economy, made much of this fact in her books, including The Death and Life of Great American Cities and The Nature of Economies. As she pointed out, the great advantage of a city architecture is its ability to support change in uses, and Jacobs correctly predicted the persistence of the city itself, unlike those who predicted the rise of the Internet would mean the death of the city.