Tick, tick, tick.
Outside the open-air pool at the Singapore Sports School the sky is cut by lightning; inside the arena a streak of aquatic genius is about to flash before us. Chad le Clos is eager, he jogs to lane two, splashes water on his face and body, as if purifying himself.
On the blocks he is still, the water is still, the clock is still. There is nothing to suggest a world record. Nothing except a voice in his head which tells him he is ready.
In white shorts on Monday, le Clos is any other fresh-faced kid. In a swimsuit on Tuesday, he assumes his other identity - butterfly behemoth. He cannot promise a record, but the chase of it is profound in itself. It is daring to believe he can go not just faster than the 7.22 billion people on the planet but all those who came before.
The Olympic gold, which le Clos owns, can never be stolen, but the world record will be. No one keeps it, no one is sure how long they will keep it. But it is a marker of human endeavour, it is single-handedly taking a species further, and this is what makes it weighty. The Olympic gold is mostly about being faster than the next man; the world record is about becoming faster than any man ever.
Tick, tick, tick.
After 50m, the crowd is looking at le Clos rather than the scoreboard where the electronic timer is dancing rapidly. There is no smell of history yet, except Graham Hill, his coach, is sitting in the stands like a man waiting for his child to be delivered.
Human beings adore records, even if it is "most toilet seats broken by the head in one minute" and "most steps walked by a dog balancing a glass of water". But it is fastest, highest, longest, toughest that compels us most. One day there will be a point beyond which a human cannot go, but le Clos is about to tell us it has not been found in the water.