How can you get from Berlin to Hong Kong for free? Apart from cycling or going on foot, which could take the best part of a year and involve much more than the price of an airfare in food and lodging, hitch-hiking might be a viable option.
That's the route Adam Shek Chi-wan is taking, anyway.
The 25-year-old former junior architect, who quit his job last June to have a working holiday in Germany, reckons it will take him five months to hitch-hike the 10,000 kilometres home. He sets off tomorrow.
"To my knowledge, I don't think anyone from Hong Kong has achieved this and therefore I want to be a pioneer," said Shek, a marathon-lover who's keen on new adventures.
When faced with the choice of staying in Germany to do a master's degree and become a fully qualified architect or finishing his year away in an "extraordinary way", Shek said the answer was clear: "Of course the crazier one!
"I think the world should work in this way: when we have spare resources, we should share them. It's the same for travel - when drivers have spare seats in their cars, why not share them with hitch-hikers?" he said.
To prepare for the epic journey, Shek tried to get his thumb in gear by hitch-hiking around Europe last month. However, he learned the thumb is not enough.
"Conventional ways like sticking your thumb out or a cardboard sign are not as effective as you might think," said Shek. "The key is to gain trust from drivers, so creating chances to interact is important."
He also learned that hitch-hiking at night is a non-starter. He spent the entire night by a motorway in Lyon, France, trying in vain to get a lift.
He said it was better to approach drivers at petrol stations. "I make eye contact for a few seconds with drivers, and then try to introduce myself in English rather than the local language to make sure we can communicate on the way."
The conversations with drivers from all walks of life were the best thing about hitch-hiking, he said. "We share our stories, it's the way to get to know the world."
Shek, now working as a freelance graphic designer, also regards the trip as a stepping stone to becoming a travel writer and photographer. He plans to work with charities to report on stories of poverty along the journey via Eastern Europe, Iran, Pakistan, India, Nepal and Tibet.
His biggest concern is the stretch from Iran to Pakistan, where tensions frequently spill over into conflict. Shek said he might be forced to detour via more obscure countries in Central Asia, such as Turkmenistan, Uzbekistan and Tajikistan to enter Xinjiang , China.
With a budget of less than €300 (about HK$3,000) a month, Shek plans to avoid hostels and hotels in favour of couch-surfing via a global online network offering free accommodation in exchange for good company.
"I am grateful for the chance to design my own lifestyle while I'm still young, as well as the support shown by my family," Shek added.
To follow Shek's journey online, check his blog http://hitchtomars.net