For Ollie and Harry Ferguson, life is an adventure. For the past four years, the brothers have been working to complete a list of 500 challenges and experiences.

"The idea came about actually from the boys," their father, MacNeill Ferguson, said. "The boys were just asked one day if they could come up with some cool things for us to go and do as a family, and they came up with some hilarious ideas initially, like go on a mission to Mars and intergalactic sausage day and all sorts of strange kids requests. And from there, Vicki and I built the list to a hundred, then kept finding new things we wanted to go and try ... until it got up to 500."

They're all catalogued on the brothers' Facebook page. So far they have built an igloo, explored the wilderness, and sent their Lego men to the depths of the ocean and into outer space.

"Well, we got a sort of box thing, attached a GoPro onto it, stuck our Lego men on with our flags, and then inflated a helium balloon, and it just went," Ollie said.

But perhaps their biggest adventure is playing out right now on the high seas. Last year, Ollie and Harry launched a toy pirate ship from the Scottish coast. The boat – aptly named "Adventure" – sailed across the North Sea to Scandanavia. It then hitched a ride on a Norwegian boat and was launched again, this time off the coast of west Africa.

Adventure traveled all the way across the Atlantic Ocean and is currently in the Caribbean Sea, about 150 miles from Venezuela. It's equipped with a tracking device, allowing the brothers to follow every step of the voyage.

But the battery on the tracking device is starting to dwindle, so Harry and Ollie hope a passing ship spots their boat and is able to recharge its battery, allowing the adventure to continue.

"I want it to go to Australia because that would be halfway around the world, and there's lots of beaches there," Ollie said.

"Harry, where would you like the boat to go?" Ferguson asked.

"China," Harry responded.