Long layover in PEK T3 - what to do
 

Well, I will probably have a 12h (!) layover in PEK with AC, waiting for a flight to LON. I will be in J, so I will have access to AC Business lounge, but still, it's a lot of time.
Any idea of what I can do during that much time? How is AC lounge? Any bed or place where to sleep?
Is there anything interesting to do/see in PEK? Obviously, I don't have a visa for China, so I can't go to BJS...
All ideas welcome. Thanks

If you're transiting from one country through China at PEK to another country, for many citizenships China has a transit without visa program that DOES allow you to leave the airport. Check the details carefully. If you plan, you should be able to see quite a bit of Beijing with twelve hours. There's a thread somewhere that suggests doing a traditional Chinese massage downtown during layovers at PEK.

I would indeed be transiting from Mongolia.
This would be an excellent news! I have lived in BJ and still know some people there!

Remember, transit without visa is only available for some passports. I would also carry a printout of the rules to avoid problems with airline checkin staff.

I am eligible. Excellent :)
Thanks a lot!!

In that case, you will have no problem figuring out "what to do", but stay out of trouble or troublesome situations because the 100 day campaign against foreigners is on in full force (there is an interesting thread about this topic in the China forum that we are considering having deleted; if you want to read it, now is the time). In any event, unless you act like a moron, you have nothing to worry about.

Um, no. Transit Without Visa (TWOV) for international through travelers is available to nearly all passports, for up to 24 hours. Perhaps you are confused with the 48 hour allowance at SHA and PVG, which is only available to a select list of passport holders (but still a lot of countries).

As for printout of rules (TIMATIC), always a good idea to take along, but it really depends on airline and origination point as to whether this will be an issue with check-in staff. All the airline staff need to know is that you will be transiting in PEK--they do not need to know (and you do not need to volunteer) that you plan to leave the airport. Plans to leave the airport are more properly addressed to Chinese Immigration, whom you will encounter upon arrival. There is a Sticky at the top of the China Forum which describes this, also numerous recent posts on the very simple TWOV procedure.

Definately suggest you leave the airport.

The super convenient airport express links right into the subway (two tickets) and you could see many things with 12 hours (or one thing at great detail).

The Forbidden City, The Temple of Heaven come to mind. . .