The Swallow's Compass
“Chiseled into the great wall which cuts across the plains of Yanxia, between two of the Dairyu Moon Gates, is the visage of Ganen, the legendary hero who united Doma. The first king of the new kingdom was not only a military genius, but also the founder of geomancy, and so after his death this royal mausoleum became a holy place to which his disciples would make pilgrimage. Alas, following the imperial invasion, it was abandoned and fell into disrepair, and none can say for certain what dangers lie within. Regardless, if Soroban's rigorous training under Genbu is to continue, you and your comrades must venture into these hallowed halls and obtain the tamate-bako of geomancy, an ancient relic with the power to manipulate time itself...
— In-game description
The Swallow's Compass is a level 70 dungeon introduced in patch 4.3 with Stormblood.