Sailing the world alone was once regarded as one of those heroic conquests like climbing Mt Everest, but now all sorts of people are attempting it.
Today 17-year-old Mike Perham slipped into the Waitemata Harbour, having already achieved half of his challenge.
Being alone onboard, he does absolutely everything on the boat himself. And although it means things take a while, he's got plenty of experience.
Mike's just arrived in Auckland after sailing from the UK, but he's only halfway through his journey.
"Nothing beats surfing down a wave at up to 30 knots in the southern ocean," he says. "The whole boat is airborne. I'm having a ball really."
Mike is a passionate sailor and is fast becoming the youngest person ever to sail around the world by himself.
Mike's spent 80 days on his voyage so far and is already dreaming about his next adventure.