CAHTT Methodology

Our new procedures now call for verification of the existence and completion of buildings not previously reviewed or documented, after we complete the initial review of all 1,000-plus buildings and towers in our growing database. This database includes the name, built date, roof and spire height, and existence documentation when deemed necessary. New buildings for which evidence of their completion cannot be found will be excluded.

In order to rank skyline heights, several methods were reviewed, and the following one was determined to reflect most closely what one would see with the naked eye if the city skylines were placed against each other; that is, which would appear taller. Most methods yielded similar results.

For each city, a review of the tallest 25-30 buildings is conducted, depending on the level of new construction, to determine which buildings are new and which are complete, and to verify in which year they can start being ranked. Because some buildings will rank differently depending on the inclusion of their spire, some buildings may not be included in one calculated score of its city's top ten, but are included in another. This also occurs when including towers. To track any corrections to height information, and prevent duplication of data for the same building, alternative building names are tracked for each city's top 30.

Dubai Construction Boom Accelerating

In a review of the data collected for 2005, we discovered that two buildings, reported as completed by December 31, 2005 in Dubai were actually not completed until February 2006. Therefore, Dubai was prematurely ranked above Houston for 2005. This significant error caused a change in the amount of data gathered, and its review, for future rankings on these pages (see details on next column on Methodology). Nevertheless, Dubai continues to build at breakneck speed, adding three new towers into their top ten in 2005, and four more in 2006. Dubai, of the United Arab Emirates, with a population smaller than that of Dallas, is undergoing a construction boom the likes of which has not been seen possibly since the building boom eight decades ago in New York City (see related article). If the current trend continues, and the all the buildings currently under construction do materialize as planned, by the end of the decade the city of Dubai will become the tallest, and most fantastic city the world has ever seen. By then, even New Yorkers will be drawn to modesty should they happen to set their eyes upon the new gleaming city at the edge of the Arabian desert.

There is a question as to the feasibility of this development. After all, one wonders how a city of a 1.2 million will support, and fill, an array of skyscrapers normally found in rich cities seven times as big. In any case, Dubai is set on completing the world's tallest building even before New York's much delayed Freedom Tower rises even one foot. This is the same Dubai that caused an uproar last year over the deal to manage major U.S. ports, that is the source of $10 million in annual earnings for former U.S president Bill Clinton through a business partnership, and that U.S. Vice-President Dick Cheney's former company of Halliburton has chosen as its new headquarters to escape U.S. taxes. In a span of a few years it has become a major world banking and financial center, tourist destination, and the main air transportation hub in the Middle East. Regrettably, it is also the same Dubai that bans all Isrealis from entering it.

Calculation Method (CAHTT)

Three separate scores are compiled for each city: The sum of the heights of its ten tallest buildings up to the roof (spire not counted); the sum of the heights of its ten tallest buildings, including the spires; and, the sum of the heights of its ten tallest towers and buildings (up to roof only). We do not consider the number of stories since they are not a good indicator of a building's actual height. The scores are added together and then divided by three.The result of this is to give more weight to actual floor space (100% value) than to spires (33% value) that are often little more than needles in the air, or towers that also do not occupy much space in the air (67% value).

China's Skylines Gain on American Cities

As we complete the rankings of the tallest 11-25 cities in the next few weeks, we expect to once again see dramatic gains by Chinese cities. Twenty-five years ago Shanghai was a fourth world city that was poorer and more backward than major third world cities like Mexico City and Sao Paulo, and had not a single skyscraper. Its transformation in that time to today's futuristic skyline rivaling that of America's greatest cities, is nothing short of astonishing. A similar transformation has been taking place in other major Chinese cities such as Shenzhen, Guanzhou, Wuhan, and Chongqing, and reflects the record growth of the economic might of China, as well as its emergence as a world superpower.

In keeping with standard practice as established by the Council on Tall Buildings and Urban Habitat, antennas are not counted. We refer to this method as the Calculated Average Height of the Ten Tallest, or CAHTT.

In ranking, categories became apparent, thus the tiers. Tier 1 are those five cities with skylines significantly higher than all others. The sub-categories of A and B note the clumping of the scores with Tier 1B cities' composite scores closely clumped around 900 (and easily switched ranks in their separate scores), while both 1A cities had notably higher scores, above 950. Tier 2 cities' scores were significantly lower than the five Tier 1 cities, and closely clumped between 700 and 810. Tier 3 are those below 700.

The survey reviews the statistics of over 1,000 buildings and towers in 30 cities.

Discussion on Methods Used by Other Skyline-Ranking Websites

This, of course is not is not the same as determining which skyline is more aesthetic, or which appears more imposing when seen by itself. It is merely a measurement of actual vertical dimension. Some visitors have pointed out to us (some boosters of Hong Kong and some of New York City) that their city should be on top because their city has more tall buildings. In fact, as recently as 2005, New York City still led in the number of true skyscrapers (185 free-standing buildings of 500 feet or more), while as recently as 2002 Hong Kong still fell behind Chicago. However, by the end of 2005 Hong Kong added an astonishing 37 skyscrapers, putting it just behind only New York with 116. When we finish our count for 2006, we may find that Hong Kong has overtaken New York in this regard as well. In any case, the problem with the approach of counting buildings is that one is no longer measuring actual height, but quantity of buildings. Certainly, a larger quantity of buildings may make a skyline appear more impressive, even if all the buildings are less than 500 feet tall, but it does not make it taller. This is why sites such as Emporis.com and Egbert Gramsbergen and Paul Kazmierczak's "The World's Best Skylines" rank Sao Paulo relatively high on their lists even though it has few buildings above 500 feet, and none above 1,000 feet. Those rankings do not focus solely on height (nor do they claim to) as we aim to do here.

Why this ranking? We believe it is one measure of the changing balance of power in our world.

World's Tallest Skylines - World's Tallest Cities - Tallest Buildings of the World - Tallest Skylines of the World - Tallest Cities of the World - Ultrapolis Project 2004