Certain cities are kind of a sleep for a long time and suddenly they become boomtowns.
Other are built to boom for ever.

What is the reason of this ?

No city booms forever, it depends on economy, and commerce... and Population. It just doesn;t "boom" for no reason, there are many factors to when a city's population and commercial market sky rockets...

If only it were that simple. There isn't one thing that makes a city boom. It's not like SimCity where you can drop your taxes to almost nothing, build lots of highways, and watch people flood in.

Mainly, it's being in the right place at the right time. Social and economic factors also come into play.

Denver boomed in the late 1990s, but it had nothing to do with the energy sector, which previously dominated the economy. Denver was a minor player in telecommunications-based industries. Young, educated, and outdoorsy professionals flocked to the city for its natural advantages. These young folks provided a talent pool for the budding dot-com industry. Many dot-coms set up shop, which resulted in attracting more young professionals, which resulted in more tech companies relocating to and starting up in town, and so on; a cycle begun. Even with the dot-com bust, the young professionals stayed behind although they lost their jobs; they didn't want to give up their location close to the slopes and trailheads.

Factors that are often cited by urban geographers when explaining why cities form where they do; being at a break-in-bulk point, location near natural resources, and so on, weren't a factor in Denver's boom. The young professionals fueling the boom weren't laborers. Consider the presence of other boomtowns that are located in what would otherwise be improbable locations for big cities according to geographers; Las Vegas, Charlotte, Orlando, Colorado Springs and Phoenix in the US, for instance.

I live in an interesting town when it comes to booms. In the 60's my town had around 5000 inhabitants, and that number has grown to 112000 in 2004. Now, in a large city an increase of ~105000 may not be so significant, especially not over 40 years, but to put it in another way, its a 2140% increase.

What happened was that the nearby city of The Hague had no place to house people working in the city, since it has exponentially more workspaces than residences due to it being the city where the government is seated. Zoetermeer (the town I live in) was only 15 km (about 10 miles) away, so they pointed this out to be a 'groeikern', freely translated a 'growing spot'. Now Zoetermeer exists of mainly fairly new buildings and you can easily see the change in architecture by looking at different quarters in the city. Its also interesting to see, when compared to other cities with of the same size, how few facilities such as shops, cinema's, and recreation it has. Now that the city has virtually no more space to build within its own municipal borders, it will probably stop at about 130000 inhabitants. They are also trying to get more people to work in Zoetermeer, but due to competition to oter cities that frankly have more to offer, this is not working out as well as it should. Right now, there are 45000 people working in Zoetermeer, and they want that to be 70000 by 2025, when the population growth should be stabilized at the 130000 mark. Already is the city trying to shed its reputation as being the 'sleeping-city' of The Hague, which works from time to time, but its still being overshadowed by its big brother. I guess only time will tell how it works out, the most succesful thing for Zoetermeer to do at this point is sell houses, since everybody wants those over here.

Sorry for the rant, but its just some firsthand news about some 'booming' in Holland.

I should point out that there are other large cities who have similar stories to tell as the one I told in Zoetermeer. Examples are Almere and Purmerend for Amsterdam and way more. I can elaborate on them or do some research if you're really interested.

The building of skyscrapers in Canaray wharf in London can be attributed to a combination of reducing planning requirements in the area and giving tax insentives to a development zone. This combined with a easing of financial regulations in the UK helped encourage fincnace companies to flourish here. Improved prosperity helped turn London from a City loosing thousands ofpeople each year to a place drawing people from other cities as the industry London is dominated by is growing whilst industry is shrinking.

It is gerneally employment and opportunity that brings people places I think.

Most times cities are booming because countries are booming. Shanghai is booming because of the growing strenght of china not because it is a very interesting city. The cities which are booming today are lying in countrie that aren't full industrialised. Most people in china live in small agricultural villages. The new possibilitys in the cities make them interesting for the farmers. In middle and eastern europe it is the same. Poland is a very much indutrialised country but a lot of people still live in small towns with big problems. So the population moves to places with better conditions. Cities are only booming within the time of industrialisation. American cities are not booming any more. Paris isnt able to grow much. The countries which have opened their borders to the open market like the old communistic countries are developing now because they are getting industrialized.

old communistic countries are developing now because they are getting industrialized

Industrialization in Poland began in XIX century with its peak in 50-70s XX c. From 80s share of industry in polish GDP shrinked from ab 50% to 31% currently (with services 66% and agriculture 3%)

In general population in Polish big cities doesnt change or rather decrease slightly - it is effected by "0" growth in population and the fact that work immigration from smaller cities/villages/other countries is balanced by many people who moved to new houses built in outskirts.

So Warsaw boom in construction works during last years doesnt mean booming population (only 5 from 30 highest scyscrapers in Warsaw are residentials!)

Low/no taxes are almost always guaranteed to lead to a boom.

It's the best way to get an economy rolling!
But if you lower them too much then the gov't doesn't have enough money to function. There's a thin line between boom and bust! :)

Industrialization in Poland began in XIX century with its peak in 50-70s XX c. From 80s share of industry in polish GDP shrinked from ab 50% to 31% currently (with services 66% and agriculture 3%)

In general population in Polish big cities doesnt change or rather decrease slightly - it is effected by "0" growth in population and the fact that work immigration from smaller cities/villages/other countries is balanced by many people who moved to new houses built in outskirts.

So Warsaw boom in construction works during last years doesnt mean booming population (only 5 from 30 highest scyscrapers in Warsaw are residentials!)

If you say a city is booming it doesnt have to grow. I'm from Lodz so i also know the situation in Poland. In most polish cities the rents are very high. (related to peoples income) This situation is caused by a massive lack of new apartment buildings. The profit you can make by building new apartments in warsaw lies between 15 and 20%. Thats really high. And industralisation doesn't mean industry it also means a growth of the commercial sector. economicaly poland isn't an that high level like the bigger industrial nations have already achieved. Just look at germany or france or even great britan. The economy has boomed in within the last ten years and it still does. Also the percentages of the economical sectors can't be
true.In 1990 30% of the polish workers have worked in the agricultural sector. Where are 90% of the jobs. poland hasn't made such a developmant. 3% is unrealistic. The netherlands germany belgium aren't agricultural countries but they have about 5%. Poland is still a very agricultural country. It's not possible that poland has just 3% agricultural jobs. Maybe these numbers count only on the city centre of warsaw.
Anyway you have just said that people are moving to the suburbs of big cities. I think they also count to the city they belong to. If you think that they dont count you have to say that Paris has only two million citizens but with its suburbs it has 10mio.

I didnt say that only 3% Poles work in agriculture - in fact about 25 % Poles work in agriculture - the problem is that they make ONLY 3% of our GDP - our agricultural production is simply not effective. These numbers will propably soon change slightly in favour of agriculture sector - thanks EU subsidies and growing prices after joining EU polish agriculture will be for sure more "efficient".
Unefficiency of Polish agriculture is visible when we compare it to Netherlands - where only 4% of pop works in agriculture but they make ab 2,5% of Dutch GDP.

Writing about outskirts I meant not suburbs but small cities outside of Warsaw boundaries that make city metro that now is counted from 2.6 to 3.0 mln pop when Warsaw total population i 1.6 mln. So I meant that population of Warsaw metro in fact grown much quicker than the population of Warsaw city itself. I cant find for it any reliable data - simply Ive met very different data for Warsaw metro area....