For nearly 2,000 years Chengdu was a key silk production center on the overland trade route from China to Europe – known as the Silk Road. But surrounded by mountainous terrain and 700 kilometers from the ancient capital Xi'an, it was hard to reach. There is even a line in a famous poem from the Tang Dynasty that says, "It's easier to reach Heaven than it was to take the roads to Sichuan." Today, that saying is no longer true.

In the documentary "The Silk Railroad," British historian Sam Willis and CGTN journalist Li Qiuyuan explore how Chengdu has been building itself into the terminus of tomorrow.

Since 2013, Chengdu has been operating direct freight services to Europe, as part of the Belt and Road Initiative. In just over four years, the International Railway Station in Chengdu, which used to cater only to domestic trains, has now spawned the busiest international terminus in China. Last year, the station moved half a million containers.

To reach China, a train has to travel more than 10,000 kilometers, passing through Germany, Poland, Belarus, Russia and Kazakhstan. Once it arrives, 600 tons of goods can be unloaded in just over an hour with an automated system. In 2016, about 1.6 billion US dollars worth of goods were moved through the Chengdu-Europe rail link.

With the trains come some high value items: cars.

China is the world's largest auto market. In 2016, more than 28 million cars were sold here. That's nearly twice as many as the European union.

More cars and a greater variety of automobile brands are sold in China than anywhere else in the world. European models are most popular, making up 45 percent of the import market.

Before there were direct train services from Europe to Chengdu, cars had to be shipped via coastal cities nearly 1,500 kilometers away. But today, trains loaded with cars arrive in Chengdu six times a week to supply China's 280 million drivers on its roads.