Hi, well Riyadh is the gulf's only mega city, looks like Dubai is following that track to become another one. Jeddah is second at the moment, anyways, enjoy:

Saudi Arabia's capital Riyadh is now home to more than four million people and it is set become the first mega city of the region, says a report. The population figure represents a 4.2 percent increase over the past eight years, according to the High Commission for the Development of Arriyadh (HCDA).

The population of the city was 4.26 million at the end of 1425 Hijrah year, which ended in February. The new figures cover adjoining suburban areas of Al-Dirayya, Al-Haer and Arqa districts, said an Arab News report.

Expatriates, according to the HCDA figures, numbered 1.46 million in the capital city, representing 34 percent of the population compared to 2.8 million Saudis.

HCDA said 63 percent of expatriates living in the capital are male, whereas Saudi male population account for 53 percent of the capital's indigenous population at 1.48 million.

The latest census showed that the Kingdom's population last September was 22.7 million of which 6.1 million were expatriates, representing 27.1 percent of the total population. Saudi males represent 50.1 percent of the total indigenous population.

Another study conducted by Arriyadh Development Authority revealed that the growth of Riyadh's population is triggered not only by natural reasons but also by a continuing wave of migration of Saudis from other parts of the Kingdom.

The population of Riyadh is projected to exceed 11.1 million by 2020.

"The population growth rate of Riyadh city is one of the highest in the world and the Kingdom's overall population is growing at a rate of 3.6 percent annually, according to a book entitled "Investment Atmosphere in Riyadh City."

Asian expatriates, the book said, represent 50 percent of the expatriate population. The average age of the population is 22 years with 50 percent reported to be under 20. According to the book, only two percent of the population is over 60 with the average age of Saudi males and females estimated at 18 and 17 years respectively.

The average age of non-Saudis was put at 32 for males and 29 for females.

My Riyadh, i love this city, such a true arabian city. not a fake one like dubai. lol. just wish it was more open though.

lol, Dubai isnt a fake city its more like a museum ;).

how is dubai a museum?

The growth of Riyadh is out of control. They had to stem the influx of local migrants by decentralising and developing other cities in the country like Medina Abha Taif Hofuf and Tabuk. Cities become unwieldy and diffcult to manage if they become too big, just look at Sao Paolo or Bombay.

Riyadh is growing really really fast. It's as Hijazy said, OUT OF CONTROL. It's spreading to all directions and it's pretty FLAT. The diameter of the city is more than 60 km. That is becoming a big problem and causing horrible traffic jams. The government is working on dividing the city to four quarter (called civil centers). Each quarter is independent from others with all the government services and shopping needs. The quarters will linked via light city trains on King Fahad Road (North-South) and Prince Abdullah road (East-West).

Most of the population growth comes from out of the city migration. I heard once that over 10,000 people migrate to Riyadh every month from all over the Kingdom. That’s over 120,000 + to the total population per year.

You guys, i'm not sure about this...but I figured it might be worth it to mention. I recall reading that the Riyadh Development Authorities might be re-zonning most of the city. They will be specifying 7 districts where high-rises will be permitted (exceeding the 30 floor limit currently impossed by Riyadh's zoning regulations). I would believe the Olaya District would be one of them. I recall that they said this is one of the solutions they are thinking up off, because they are affraid that the city might start experiencing services and utilities failures on the outskirts because its growing faster that city planners and developers had ever expected.

I have read in the paper a while ago, about the zoning of self contained satelite cities with local branches of government/public services. 4 zones + central Riyadh. It was in alRiyadh newspaper.

This is good. Riyadh, and jeddah are probably the only two real cities in the whole Gulf. The growth of these cities is amazing. I wish alot of red tape would be cut, because a city like riyadh has the right market for pretty much any project you can think about. I wish it was more commericalized!!

Excellent city Riyadh, good it will have 11.1 million by 2020.

This is what i call rapid growth. I've been to Riyadh and for a city that big, it really needs more entertainment in it i.e. more things to do besides a few shopping malls.

I have read in the paper a while ago, about the zoning of self contained satelite cities with local branches of government/public services. 4 zones + central Riyadh. It was in alRiyadh newspaper.
Yesss, that was I saying.
You just put it in a more brief professional way :)