By Duncan Walker
This week the BBC News website is looking at people who do unusual jobs. In the first of the series we speak to a man who makes his living being fired out of a cannon.
Human cannonball Diego Zeman is fired twice a day. Boom boom.
Shot from a four metre gun, the circus stunt man flies through the air at speeds of up to 60mph, his mind always firmly set on that distant safety net.
Diego comes on to the strains of Rocket Man
The crowds roar, wide-eyed children clamour for his autograph and the hours aren't bad. But it's not an easy life.
"I always feel nervous," he says. "I have to concentrate, everything has to be 110% perfect."
Get the timings wrong and it's not just your job at risk.
For 24-year-old Diego, the circus life was always going to be a career option.
His Brazilian father and Hungarian mother were part of a big top acrobatic act based in Eastern Europe.
The young Diego grew up around the performers and started training when he eight. "I was born into the circus and started with the trapeze and high wire," he says.
Moving on to the job of human cannonball was therefore, for Diego at least, an obvious next step.
Diego starts his act at Cottle & Austen circus to the strains of Rocket Man, the dimmed lights suddenly turned on to reveal him standing on top of his cannon.
It's then a question of clambering inside the barrel and standing on a platform three quarters of the way down.
Air is pumped at high pressure into the space left beneath his feet and, after final checks to make sure he is ready, his flight begins.
"I feel free when I'm flying - it's a nice feeling," says Diego. "It's a bit like bungee jumping."
Two seconds later it's time to land in the net. Job done.
To suggest it's easy work is to miss the point though. Diego is not just 60-odd kgs of human ballast - his task requiring more talent than the audience might realise.
The troupe work together during the two hour shows
Apart from facing the strains put on his body by the sudden acceleration, the flying Diego must also perform something of an acrobatic feat mid-air.
"You have to fly straight, keep you body rigid and turn at exactly the right moment so that you land on your back," explains cannon trainer Marnie Dock, who was the world's first female human cannonball at the age of 16.
There is also the small matter of making sure that Diego is not fired headlong into the big top's canopy, or the many wires strung-up for the circus' acrobats, says Marnie.
Every time the circus moves, the cannon's position and angle is precisely calculated.
A dummy model of Diego is test fired several times to check everything is okay before the man himself starts work.
Anyone tempted to explore a career in human cannonballing themselves may also need to look more closely at what's involved.
The pay isn't great - this is a job done "for the enjoyment, not the money" - and you have to live on site.
And while your act may last just a couple of minutes, the circus requires your presence throughout the shows as part of the troupe.
Diego also has to control his weight (lest those calculations get messed up) and spends an hour or two in the gym every day, to strengthen his knees and back.
He has also been to the Guyana space centre in French Guyana, completing a course which helped him prepare his body for the rigours of being propelled at high speeds.
Ironically it was his predecessor's fear of flying in planes, as opposed to out of a cannon, that led to the job coming up when he refused to travel to South America for training.
Perhaps those with similarly nervous dispositions could plump for an easier job. Knife thrower's assistant anyone?