In 2009, Chicago Leads Again,
But in 2010 Dubai is New Number One
Bad Data on the Internet
After a review of the 2005 ranking data, it was determined that two towers, the Al Fattan Towers, reported as completed in Dubai by December 31, 2005, were actually not finished until February 2006, resulting in incorrect scoring for Dubai for 2005 (now corrected). A broader review exposed additional bad data in a few of the cities ranked. Another major correction to the information we had was the removal of the Grand Duta Hyatt in Kuala Lumpur, a building still reported as completed in 2004 by various sources, but that was never actually built.

A subsequent investigation determined that many of the most respected websites and hard-copy sources publishing skyscraper and other building information had incorrect information, which was often repeated by different sources, or published data in an inconsistent manner.
In 2009, as has been the case with every year this last decade, we saw significant ranking changes. In determining the rankings of the world's 25 tallest cities as of December 31, 2009, we continued to find that almost all of the construction of supertall skyscrapers is in Asia (for top 25, see left link). Of the ten tallest cities of 2008, only Hong Kong, Kuala Lumpur, Houston, and Shenzhen did NOT introduce new buildings into their own top ten tallest, and kept their scores static.

In 2009, Chicago added to its skyline the tallest building built in the Western Hemisphere since the Sears (Willis) Tower was completed in 1974. The Trump International Hotel and Tower, at 1,362 feet (415 m), was 9th tallest in the world when it was finished, and was the tallest completed in 2009 (it now ranks 10th, and we project will rank 11th by the end of 2010). This put Chicago back at number 1 at 2009's end, but only briefly.
Current Procedures
Our 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.
Singapore Edges Up, Beijing Rockets Up
Among the top ten, in 2009 Singapore moved up to 7th, past Houston and Shenzhen, pushing those two down to 8th and 9th respectively. Among the top 25, Beijing catapulted forward from 29th to to 16th, after completing three new major skyscrapers, including its two tallest, and entered the top 25 for the first time.
Dubai Game-Changer in 2010: Khalifa Tower
In 2010, the major developments so far have been headlined, of course, by the completion of the long-awaited Burj Dubai, now called the Burj Khalifa ('burj' meaning 'tower') in Dubai. The super skyscraper is in a category all its own, reaching so far into the sky, over half a mile, its nearest competitor in Taipei is dwarfed by it. Since the Empire State Building was completed in New York City in 1931, all the height gains of its successors have been incremental (WTC, 9%; Sears Tower, 5%; Petronas, 2%; Taipei 101, 13%). The gain of the Khalifa Tower over the Taipei 101 is an astounding 63%. This is the true heir of the visionary impulses that raised the Empire State Building. And, like the Empire State Building, which captured the worlds' imagination and remain unrivaled for nearly 40 years, anyone over 40 is unlikely to ever see the 2,716 foot (828 m) Khalifa Tower matched, let alone surpassed.

Thus, with the completion of this new super tower, and three other major skyscrapers in Dubai, Dubai handily takes the lead as the World's Tallest City (for more on Dubai's rise, see the World's Tallest City).
Guangzhou Breaks Top Ten, Moscow Follows, Passes Beijing
The Dubai developments pushed Chicago down to 2nd place. Then later in 2010 Hong Kong completed its newest tallest building, the 1,588 foot International Commerce Tower, ranked 4th in the world, which allowed Hong Kong to slip back into 2nd place, and left Chicago now in 3rd. As a result of Dubai's final step up, Shanghai moved down to 4th from 3rd in 2009.

The other major change among the top ten so far in 2010, has been the ascension of Guangzhou to 6th place from 13th, pushing Singapore, Houston, Shenzhen and Toronto down a notch. However, Toronto added a new building to its top ten, allowing it to move past Shenzhen (pusing it down another notch), and to remain in 10th place.

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).
The Outlook: China Gains; America Fades
There is a question as to the feasibility of the rapid development in Dubai. 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. This is the same Dubai that caused an uproar in 2006 over the deal to manage major U.S. ports, that was 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 chose as its new headquarters to escape U.S. taxes. 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.

We expect to continue to see dramatic gains by Chinese cities, as the former pre-emimence of American cities fades. 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 2008 it surpassed Germany as the world's 3rd largest economy. In 2010, successive headlines have announced China's new number one ranking as world's greatest car manufacturer, number one consumer of commmodities, and its expected surpassing of number 2 Japan in economic output this year.

As for American cities, after almost twenty years of very little changes in their skylines, the only new architectural vigor evident is in Chicago and Miami. Miami, in particular, completed eleven buildings of 500 feet (150 m) or more, in 2008. However, this was likely an echo of the real estate bubble of the mid-2000's, and is not likely to continue in the near term.

For more on Dubai, Chicago, and New York City, and their skyline building histories, see the article links at upper left.
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, between 2000 and 2007,closely clumped between 700 and 810. Between 2000 and 2007,Tier 3 are those below 700. For 2008, the 730 is the new minimum score for a Tier 2 classification.

The survey reviews the statistics of over 1,000 buildings and towers in 35 cities, and does an annual cursory review of a dozen more potential qualifiers for the top 25.
Discussion on Methods Used by Other Skyline-Ranking Websites
The above approach, of course is not is not about determining which skyline is more aesthetic, or which appears more imposing when seen by itself, as other skyline ranking sites aim to do. It is merely an objective measurement of actual vertical dimension.
W
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. 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.
W
© The Ultrapolis Project, 2004- 2010
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 2009