With 108 days as our canvas, we began the process of modern map-making. Our first big decision was about our travel style: do we plant ourselves in one place to go deep, or do we seize this rare opportunity to see multiple corners of the globe? We chose the grand tour.

Our expedition headquarters was a suite of digital tools that would have been the envy of Magellan. We began with:

• Polarsteps to visualize the potential arc of our journey, its elegant lines tracing across continents making the dream feel tangible. But for the complex matrix of possibilities, we needed more analytical power.

• Google Flights: What few travelers realize is that its simple interface is powered by the incredibly complex ITA Matrix software, an algorithm that can compute billions of fare combinations in seconds. We used its "Explore" feature not to find flights to a known destination, but to let pricing dictate our path. By setting our departure region and dates, the map would populate with possibilities, revealing economically viable routes we’d never have conceived of on our own.

• Our secret travel agent was Gemini, an AI tool that did more than the other AI tools we tried. When we gave it an ambitious itinerary for Argentina and Chile, it warned us about "travel fatigue" and helped us create a smarter, more sustainable route. We loved its problem-solving approach, which helped us turn a dream into a realistic plan.

• Wanderlog: A cool app that helps you figure out how long to stay in each city. It even has an AI feature to help plan, but we needed to sort out flights beforehand.

It was during one of these digital explorations that our entire expedition pivoted. Our initial focus was Oceania. But the algorithm revealed an intriguing and remarkably affordable flight path: a direct trans-Pacific crossing from Santiago, Chile, to Sydney.

This single data point changed everything. Santiago, a city of nearly 7 million, sits in a unique geographic basin, walled in by the Andes to the east and the smaller Coastal Range to the west. This position makes it one of the most critical aviation hubs in South America, the continental gateway to Oceania.

Suddenly, our map expanded. A month-long South American prologue became not just possible, but logical. And if you know Paolo well, for him everything must be rational.

We sketched a route through Argentina and Chile, carefully avoiding the high-altitude Altiplano—unsuitable for young children's physiology—and focusing on Patagonia and the coast. The expedition had found its narrative thread, a westward circumnavigation shaped not by old sea lanes, but by the invisible currents of global airfare.