This plan shows Herod’s Palace in Caesarea, which he built on rock that projected out into the sea. A swimming pool was carved out of the rock and surrounded by pillars and rooms. In between the pillars, receptacles for flowers and plants were cut into the rock.
After Herod’s death, Caesarea became the seat of Roman government. The governor resided in this palace and it is thought that Paul was kept a prisoner nearby (Acts 25.4).