It's quite easy to google information about which civil airport has the longest runways, but what I'm really looking for (and having a hard time to find) is which airport has the longest runways in total - I mean if you add up all the lengths, disregarding the direction - which one be the winner?
Best I can find, within the US, is KDFW with 80,403' of total length. Second seems to be KDEN with 76,000'. Glanced at KORD, and with mental math it comes up to about 71,000'. Most other major airports are well behind all of these, mainly because they don't have as many long runways as DFW and DEN.
Somebody else can consider Russian, Chinese, and Middle Eastern airports -- I don't have the chart sets handy for those. May be worth converting this to a community wiki answer if any of those places give interesting results.
Qamdo Bamda Airport (ZUBD) has one runway that measures 18,045ft.(5,500M) long