The granite column splits the canyon into two parts, forming two accesses resembling two open gates which have been dubbed "Fushou Gate", literally meaning the "gate of happiness and longevity". It was formed when the granite body was weathered and eroded by running water along its vertical fractures (joints) and then underwent gravitational collapse.
On the left side is the gate of happiness and the right side the gate of longevity. Which gate did you pass through? If you want to be blessed with both happiness and longevity, try circling them both.

(1) (2) (3)
①The granite at the flanks of the canyon was eroded by running water along its vertical joints (factures).
②Gravitational collapses occurred at one side of the canyon and left only one granite column.
③The granite column split the canyon into two passages, resembling two open gates.