Introduction to Longmenjian Grand Canyon: It is a typical karst landform, with a total length of 15 kilometers. It is the largest valley in Beijing. It has steep mountains and mountains, winding and towering cliffs, and strange peaks. Cave, green grass and clear springs; dozens of groups of landscapes such as "General's Stone", "One Line of Sky", "Black Dragon Pond", etc. form a strange gallery in the Grand Canyon, fully displaying the wonders of nature and the magical power of the axe.