Sometimes, when you sit for a long time waiting for things to happen, and you get comfortable, and it's a little cold ... well, who amongst us hasn't nodded off for a moment?
Even, say, the president of Russia?
Cameras caught Russian President Vladimir Putin looking a bit heavy-eyed during Friday morning's Opening Ceremony, as the long Parade of Nations made its way through the Bird's Nest in Beijing.
While it's impossible to say for sure without asking President Putin directly, cameras did zoom in on the Russian leader as Ukraine entered the arena. With his hands folded in his lap and a relaxed pose, he appeared to momentarily close his eyes, before suddenly picking his head up wide-eyed and looking around.
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Of course, the head nod and closed eyes could have been symbolic too -- Russia has massed more than 100,000 troops near its border to Ukraine, as the world waits with bated breath to see if Putin will invade.