<正>A caravan of 120 horses and mules laden with raw tea left Simao in southwest China's Yunnan Province in April this year. It's expected to arrive in Beijing in September for an auction of Pu'er tea carried more than 4,000 kilometers across many Chinese provinces. During the five-month transportation process, the tea will ferment and turn black. It was on this route that Pu'er tea was first brought to Beijing 300 years ago as tribute to the imperial court from