The old aqueduct A (旧用水路A?) is an area into which Leon falls after Salazar opens a trapdoor underneath him.
A merchant and a typewriter are present in this room, along with the corpses of many Zealots who did not survive the fall. Harmless bats fly around the area.
This area marks the first time the Striker is available for purchase. Leon can climb a ladder heading into the sewer which leads to the old aqueduct B, but should make sure to pick up the Crown before leaving as it has the potential to become the most high-selling piece of treasure in the game.