The coldest phase of China's Spring Festival travel rush

Amidst the most chaotic time to travel in China, as millions make their way home to celebrate the Chinese New Year with loved ones, I found myself in a -20 C tunnel in Heilongjiang province at midnight, where the coldest phase of China's Spring Festival travel rush — an annual human migration which is considered the world’s largest — unfolds. In the hush of night, tunnel maintenance technicians scan every inch in near‑freezing temperatures and in almost complete darkness, ensuring that all Spring Rush journeys reach their destinations safely.