Your impressions of Beijing may be built on news stories of pollution illustrated by stock photos of people on bicycles from the libraries of the international media.
As the international traveller will know, the overall reality is very different from media portrayals. We lived there from 2003 to 2008 - thus seeing all the development leading up to the 2008 Olympics.
The changes have been dramatic. The bicycles diminished (though still many to be seen), the buses and taxis were replaced (almost overnight). Old districts were redeveloped. Beijing has clearly arrived as a modern cosmopolitan city.
We lived in the North near the Olympic Stadium and I worked in the North West university district so my life revolved around the North Fourth Ring Road which connects these areas. There are a very large number of young people evident in the streets - university students (including many from overseas, from Koreans to Westerners learning Chinese). Migrant workers must have left many villages of older people back in the countryside.
When we first arrived there were still a number of tapered brick chimneys reminiscent of the industrialisation of England and reminding me of the paintings of JS Lowry - a time when perhaps the first tall buildings were built that allowed the ordinary man to look down on the bustling populace from a height.
By the time we left these chimneys were a rarity - much of the city had been redeveloped and re-paved.
Compared to the boring cubic office blocks of 1970's London (no doubt built at the lowest possible cost) every development in Beijing seeks to distinguish itself with some flourish or another - a curve to the roof, a high tech cladding - or often a lot more. Perhaps the wider use of computers has made it easier to construct bespoke buildings, but it still speaks of a desire to stand out from the crowd and symbolizes the intense competition that takes place in business. It is not all large companies either - the city is teeming with people pursuing their dreams. It might seem as if in an economy growing at roughly 10% per year it would be easy to launch a startup and survive on new customers - but appearances are deceptive and small businesses often disappear within months of opening.
In most of the city it is trivial to flag down a taxi and the cost quite low so this was the normal mode of travel - though increasingly supplanted by the metro as the system rapidly expands. There are some people on the streets most of the night and it is very safe to walk around most areas - it vies with Tokyo to be the safest city I have lived in.
It is possible to buy almost anything you want from designer goods to foreign foods - but my favourite was the electronics stores of Zhonguancun - large complexes filled in part with many small booths all competing with each other - where I could buy all the parts needed to build or upgrade a PC or get some repair made to a component that would just be discarded in the west when broken.
It was interesting to see experiments in the uniforms of Police and security guards. Traditionally authority has come from the army and security uniforms tended to imitate green uniforms much as in the west they imitate Police uniforms - but as we lived there I saw some experimentation as Police and security guard uniforms evolved. Some guards wore the light blue uniforms and baseball like caps styled after some Japanese Police - but in the end the Police seemed to adopt a uniform influenced heavily by that of the British Police.
Censorship is not very subtle. Occasionally the CNN screen would go black for the duration of a news story (I wondered why the never-ending CNN ads were not canned and played back in place of the censored story - then I might not have noticed). Attempts to reach some websites are met with indications that the site or page was not found. This was a nuisance and maybe more so now the Olympics are over but Beijing does not seem at all like a grey totalitarian society - in many ways there is great freedom and people did not seem reluctant to talk.
The Chinese language is obviously fairly challenging. It is not as difficult to speak as you might imagine once you get over the initial hurdle of the tones. The Pinyin romanisation is at least logical and the grammar is not complicated. Today there are many electronic dictionaries which can help with translation and it can be fun learning some basic characters... but serious reading and writing the Chinese script does require a lot more effort. The numbers of English speakers are increasing - it is not unusual for a proud parent to push their child to speak to you in English as you share an elevator.
Climate - Although the winters can be cold with temperatures down to -10 DEGC or below at times, the houses are equipped to handle it and often you will be warmer in the winter than someone living in Southern China. When I went out I was well wrapped up - it did not prove to be the problem I had feared - partly because the winters are quite dry. For me the summers where not a problem - I am used to quite hot countries.
The pollution is not as bad as you might think. Many days of blue skies and fresh winds but there are also days with poorer visibility - dust from building sites is often cited as a cause (local sources of industrial pollution have been greatly reduced), though dust blown from inland deserts and loess plateaus is another major factor.
Exhaust from the numerous new cars is also a less obvious constituent - though overall I was not really troubled by the more polluted days.
I really enjoyed living in Beijing and would not hesitate to accept another posting there.