The Ancient Altar is the standout, with 8 of the 10 marked spots on the Operation: Egg Heist map gathered in one area, four times what the Mountain Sanctum offers with its 2. If you want the most Simple Iron Chests in the fewest trips, start there. The Simple Iron Chest is a container you collect from the map, and clearing the Altar first means you pick up the bulk of them before you ever need to think about the second location.
Areas with Simple Iron Chest
| Area | Level | On the map |
|---|---|---|
| Ancient Altar | — | 8 |
| Mountain Sanctum | — | 2 |
The Mountain Sanctum is the quieter alternative, worth a look when you want a break from the crowd of markers at the Altar and prefer to tidy up its two spots on foot. Wherever you stop, park up and cover the nearby markers on foot rather than driving between each one, since they cluster tightly enough to walk. As you go, keep an eye out for the Ornate Wooden Chest, in sight of most spots, the Exquisite Relic Chest at many, and the Simple Stone Sarcophagus near a good few.
Open the Aniimo interactive map to see it with every other filter, or pick another from the list.