Anyone getting that "aw shucks, where are the black helcopters?" sinking feeling is asked at this point to bear with us. Or rather, accompany us down to Shigatsi - also reputed to have a large PLA base. And, lo and behold, even though the place is lo-res, there's no hiding a 5km airstrip:

Crikey. Shigatsi's around 160km westish of Lhasa and a short airhop from Bhutan and Nepal. Strategically placed? Looks like it. It's a bit further from our final destination, though (1,300km, more or less). Welcome to Lake Kokonor, way up there in Qinghai:

Lovely. Kokonor is China's (or Tibet's, if you will) largest salt-water lake, is considered sacred by the locals, and is an annual stopover point for thousands of migratory birds. It's also surrounded by a whole cadre of Chinese military installations, such as this one...

...and this mystery assemblage of buildings:

In fact, Lake Kokonor is pretty well China's black ops central, if the intelligence is to be believed. Beijing is reckoned to have nuclear missiles sited around the lake (have a look if you like - they're elusive blighters) and uses the area to conduct various military tests - many of them nuclear.