北京多山。山多峡谷也多，届庸峡谷就是其中之一。届庸峡谷有很多名字。因是燕山与军都山的分界而被称为军都径；因是居庸关的所在地而被称为居庸塞Z因塞中古来关多而被称为关沟。关沟长40里，除了是古军事要塞和屏护北京的门户、自北京通往西北的主要交通孔道外，它还是条迷人 Beijing mountainous. Mountain and more canyons, the session is one of Yong Canyon. There are many names in the Canyon. Because Yanshan and the military are the dividing line between the mountains and is called the military path; because the location of the Juyongguan known as the Juyongsai Z plug because of the Middle Kingdom and more known as the Guan Gully. 40 years off the gate, in addition to the ancient military fortress and shield Beijing’s gateway, from Beijing to the northwest’s main traffic channel, it is still fascinating