Planning before Cerdà (in Barcelona) and Haussmann (in Paris) was mostly done for the sake of the ruler/military/fire safety, case in point of the latter being the rebuilding of London (Sir Christopher Wren's plan, which wasn't put into practice) after the great fire of 1666; and the rebuilding of Lisbon after the great earthquake of 1755 (Pombaline style). Basically the cities evolved over time as disasters gave opportunities for rebuilding, and a king wanting to stamp his name on future generations would often build opulent palaces (Versaille being a prime example) and places of worship (Durham cathedral another good example). If the central zones of a city became to complex and crowded they would be difficult areas for the military to control, and therefore they were often razed after an eventual rebellion. But over time, as the rule of society passed from kings and clergy to the bourgeoisie cities began to change.

A prominent pre-Cerdà/Haussmann example of a new-built city, which was made to be both modern and glorious is Washington DC. Pierre Charles L'Enfant plan laid out the city in grids to facilitate easy access, fire-safety, and incorporating stately buildings and monuments at predetermined places within the city.

Modern urban planning begins with Cerdà and Haussmann, and especially focused on allowing cities to function effectivly as economic and social entities. Therefore public health and safety because a new focus, realized by adding ample green zones, proper sewer systems (often an overlooked achievement for the 19th century), and by an orderly approach to traffic and residential zones.

For more information on the topic of urban planning I'd recommended this book, it also covers the history of the subject: Stephen V Ward (2002) Planning the Twentieth-Century City. John Wiley & Sons Ltd. ISBN 0-471-49098-9

Could you expand upon your idea that today's cities have a unified design? Each of today's modern cities are still very diverse and are products of their various unique histories. You prompted me to look back at the book New York, Chicago, Los Angeles: America's Global Cities by Janet Abu-Lughod, who wrote:

Generalizations about the nature and functions of global cities in the contemporary era tend to underplay variations that arise form the unique national institutions that serve as the context for their development... Because the built environment is itself the accumulated product of past forces, it is impossible to differentiate present effects from past residual influences, much less distinguish between those that have been shaped by local social and physical conditions and those generated at the international level.

Most of the modern cities you listed also existed in the 15th century, and the transformation from medieval to modern took place incrementally at different times and for different reasons in each place.

Hopefully someone can expand on how people hundreds of years ago may have understood the idea of cities, but I imagine it's equally difficult to generalize across various locations in that time period.

To question the question, what do you mean white painted houses? I was unaware that was supposed to be a standard feature of all these cities?

And while these cities do have some common features do we really think they are that uniform? Maybe a postcard photo gives that impression, not sure it's reality.

Edit: to expand, I think that the features that kind of need to be quite uniform are thus, ie roads, lighting, tall buildings. But everything else in a given city tends to be quite individual still, IMO. And not all cities even have tall buildings. For example, Dublin is well known for being very low-rise, though granted it's not on the scale of the cities you mention.

The white houses thing just seems a little bizarre though. Not sure where that's coming from!

Answering partly the modern city question:

• Skyscrapers, steel-frame construction, and elevators didn't exist at all until the 1880s. The first commercial tall towers (over ~10 floors) were built at the time, beginning in Chicago. Taller skyscrapers were built in the 1930s, just prior to the Great Depression, or as it began. For various reasons, very tall buildings are often a lagging indicator of boom times. The Empire State Building was the tallest building in the world for nearly 40 years until the World Trade Center topped out in the early 1970s.

• Towers started being built again post WWII, first in the US. Tall buildings appeard in New York and Chicago especially. This continued through the 1970s, slowed after the oil shocks, then took off again in the 1980s and 1990s, and of course, post-9/11 with the rebuilding of the World Trade Center.

• I can't speak much to the emergence of global "tower cities", though James Burke covers some of this in Connections. As oil wealth flooded into the Gulf region, cities such as Kuwait City literally leapt from the desert in a decade or so, and were well established by 1979 (the date of the book and TV series), with signature high towers (e.g., Kuwait Towers, which doubles as a part of the city's water supply).

• While parkways and boulevards (from a Dutch word for "bullwark") date to the early 20th century and 19th centuries -- the latter had military / civil control elements -- freeways or expressways largely date to post WWII. The US Interstate Highway System wasn't begun until 1958. Originally slated for completion by 1969, it wasn't completely built to initial spec until 1992. Robert Gordon discusses this and other elements of transport in great detail (US).

In general: tower cities outside New York and Chicago are a product of the 1970s onward, particularly as oil and wealth became available. Major development of Singapore, Dubai, and Hong Kong is since 1970, much of it dating after the 1980s. Tokyo was massively attacked during WWII (as were many German cities and much of London), and construction post-dated that. The Japanese economy was recovovering/growing post-war, but was a small fraction of the US's. By the mid-1950s, $1450/person GDP US vs. $100/person Japan, $60/person India. Shanghai and much of China's modern rennaisance has occurred since the /r/history cut-off date ;-) Vaclav Smil has some fascinating recent material resource stats on that if you're interested, staggering.

Robert J. Gordon, The Rise and Fall of American Growth (2016)

Daniel Yergin, The Prize (1992)

James Burke, Connections, (1979)

Harrison Brown, James Bonner, John Weir, The Next Hundred Years, 1957.