因地势险要，素有“两京锁钥无双地，万里长城第一关”之称。

Due to difficult terrain, known as "two lock and key unparalleled in Beijing, the Great Wall the first hurdle," said.

youdao

因地势险要，素有“两京锁钥无双地，万里长城第一关”之称。

Due to difficult terrain, known as "two lock and key unparalleled in Beijing, the Great Wall the first hurdle," said.

youdao