3015 CHINA (Gansu) - Yumen Pass - part of Silk Roads: the Routes Network of Chang'an-Tianshan Corridor (UNESCO WHS)

3015 The ruin of The Small Fangpa Castle at Yumen Pass

Yumen Pass, or Jade Gate or Pass of the Jade Gate (named for the many jade caravans that passed through it), is a pass of the Great Wall. During the Han dynasty (202 BC - 220 AD), this was a pass through which the Silk Road passed, and was the one road connecting Central Asia and China, the former called the Western Regions. Although the Chinese guan is usually translated simply as "pass", its more specific meaning is a "frontier pass" to distinguish it from an ordinary pass through the mountains.

The original Jade Gate was erected by Emperor Wudi (Emperor Wu of Han) soon after 121 BCE, to strengthen the stability of the western frontier, and its ruins may still be seen about 80km to the northwest of Dunhuang which was, until the 6th century, the final outpost of Chinese territory for caravans. By the 6th century, as caravans favoured the northern route via Hami, the pass was abandoned. With its 10m-high mud walls pierced by four gateways, the square enclosure covered more than 600m2 in the midst of unbounded desolation. 

Yumen Pass is part of the UNESCO World Heritage Site Silk Roads: the Routes Network of Chang'an-Tianshan Corridor, about which I wrote here.

References
Yumen Pass - Wikipedia
Yumenguan Great Wall - Travel China Guide

About the stamps
The first two stamps are part of the series Protecting the common homeland of mankind, about which I wrote here.

The third stamp is part of the series Beautiful China (2), designed by Ma Lihang and issued on May 12, 2016.
• The Snow Country (0.40 CNY)
• Wanfeng Peaks Forest (1.00 CNY) - It's on the postcard 3015
• Sand Lake (2.00 CNY)
• Xixi Wetland Park (4.20 CNY)

The last stamp is part of the series The 150th Birth Anniversary of Sun Yat-sen, designed by Wu Guanying and issued on November 12, 2016.
• Museum of Dr. Sun Yat-sen (1.20 CNY) - It's on the postcard 3015
• Bronze Statue of Sun Yat-sen (1.20 CNY)
• Sun Yat Sen Memorial Hall in Zhongshan Park (1.50 CNY)
• Sun Yat-sen Memorial Secondary School (1.50 CNY)

Sender: Hong Yangyang (direct swap)
Sent from Nanchang (Jiangxi / China), on 04.03.2017