These days a shipment of tea from a warehouse in Shanghai can reach Tibets capital of Lhasa in a matter of days. Thanks to the recently constructed railway to "the rooftop of the world", a tea merchant can now accompany his shipment on the long journey in heated and pressurized comfort. Pressurized of course because the train hurdles along at elevations as high 16,640 feet above sea level. (You read that correctly.) Now, people in Tibet have been drinking tea for many, many centuries - stories of hot yak butter tea are legendary. But how did the tea get there prior to the construction of the great iron road in the sky? If you answered "by truck", very clever, but were talking even further back. If you answered, "by pony", again very clever but many parts of the journey werent accessible by pony. The correct answer is that tea, pressed into the form of bricks for ease of transport, was hauled up to the mountain kingdom on foot. And just how impressive a feat was that? An examination of the new rail line will help put it in perspective.For its entire length, the new railroad sits at over 13,100 feet high. The highest station, in the town of Nagqu, is situated at 14,764 feet. As mentioned, the cabins of the train are pressurized to compensate for the lack of oxygen at these altitudes. Now, imagine yourself carrying 300 lbs worth of tea bricks on your back and covering approximately 6 miles per day walking along the tracks.Without exaggeration, that is how tea bricks once made their way to Tibet. The only saving grace was that merchants packed the tea into large packs with a built in tri-pod that allowed them to rest the towering loads up against a wall - that, and the magnificent views. The journey took weeks, sometimes months depending on weather. You can see why for centuries tea bricks were used as currency - with each step their value literally raised with the altitude. Subsequently, wasting tea was considered something of a sacrilege in ancient Tibet.