Tens of thousands of 'van lifers' and 'grey nomads' drive around Australia each year. But the iconic road trip has a surprising origin story involving a pair of missionaries, a retired butcher and a gun-slinging mother-daughter duo.

David Riley is a pastor and father who was on a lap around Australia with his wife and three children when he heard about the surprising origin story of this great road trip.

In 1925, two young men set off from Perth to Darwin in a tiny French car nicknamed 'Bubsie'.

They were running an errand for their Church – instructed to set up a Seventh-Day Adventist Missionary outpost in the Northern Territory, then to turn around and come back home.

Nevill Westwood and Greg Davies battled flat tires, evil cows, losing their way, leaky fuel tanks, dangerous river crossings and a falling out along the way.

With the help of First Nations people and station owners they met along the way, they made it to Darwin.

But when they got to Darwin, they just kept going, entering into a race with a retired butcher and a gun-slinging mother-daughter duo to become the first vehicle to circumnavigate Australia.

For David, researching and writing the story down became a powerful way to preserve the memories of his own family's lap around Australia, after receiving terrible news.

Bubsie and The Boys: The First Journey Around Australia by Car is published by SIGNS.

Early next year, Bubsie's sister car, a 102-year-old Citroën, will drive around Australia for the 100th anniversary of the original journey. The trip will be raising money for Canteen and Brain Child. Information about the trip will be online early next year.

This episode of Conversations was produced by Meggie Morris, executive producer is Nicola Harrison.

It explores travel, road trips, Australian history, modern history, motoring history, great global road trips, grey nomads, caravanning, van life, historical records, religion, church, cancer, losing a daughter, brain cancer, grief, driving, driving Western Australia, madman's track, white history, black history.