A Chinese father has taken his 4-year-old daughter on the trip of a lifetime. Dou Haobei, 26, bought a trailer for his daughter, whom he calls Dou Dou, and hooked it up to his bicycle. They set off from Dongguan in south China's Guangdong Province on April 2. They spent 71 days cycling to Lhasa in Tibet Autonomous Region. Dou said the journey was his gift to his child, who celebrated her fourth birthday in April. Dou said he hoped the journey would help his daughter grow. He wrote her a letter telling her to stay strong and persistent when facing difficulties.