'So then I knew for sure it was the Russians taking pictures of me from the underwater windows'

The building of the Berlin Wall, the Cuban missile crisis and Mark Spitz's moustache. What? Normally, an Olympic swimming champion's facial hair would not be considered a key factor in the US-USSR Cold War skirmishes of the 1960s and '70s - but Spitz reveals a little-known fact.

He recalls the start of the 1972 Munich Olympics, where he would create history by winning seven gold medals. 'You have to go back to the way people looked then,' the American legend says. 'I'd tried before to grow a moustache and couldn't, so when I finally succeeded I was immensely proud of it. When I went to Munich I had every intention of shaving it off, but then a strange thing happened.

'We only got a chance to train in the Olympic pool twice before competition. There were other pools to warm up and train in but because there were so many countries everybody only had two chances in the main pool. I wanted to go to the pool at exactly the time I would be swimming the finals, about five or six o'clock in the afternoon, but our two allotted times were early in the morning and late at night.

'The day before the opening ceremony the Russians had the pool in the late afternoon. I went over there and asked for permission to swim and they allowed me to use the outside lane. There were these underwater windows at each end of the pool and I noticed flashbulbs going off - there were people behind the windows taking photographs of me. So I started swimming with this really crazy stroke, a stroke that had the worst technique you could imagine.

'When I finished my warmup and was sat at the end of the pool one of the Russians came up to me and said: 'I've seen you swim from a distance and I've seen you swim on television but I never realised you had such a strange stroke'. So then I knew for sure it was the Russians taking pictures from the underwater windows.

'Then in the next breath he asked me: 'So what are you going to do about the moustache? Isn't it going to slow you down?' Now I don't know what possessed me to come up with this but I said: 'Actually, it doesn't slow me down. It deflects the water away from my mouth, allowing my body to stay more streamlined and not climb as high out of the water for a breath. So in fact it helps me go faster'.