Piscina Mirabilis

About

The Piscina Mirabilis, meaning "wondrous pool," is a monumental Roman cistern situated on the western hill of Bacoli, overlooking the Gulf of Naples. Constructed under Emperor Augustus, it originally supplied water to the fleet at Misenum and the surrounding villas, drawing its supply from the Aqua Augusta. The cistern’s massive dimensions—15 m tall, 72 m long, 25 m wide—give it a capacity of 12,600 m³ (about 5 Olympic‑sized pools). Architecturally, the interior forms a hypostyle hall with 48 columns arranged in 12 rows, creating a series of five long naves and thirteen small courtyard‑like chambers; the vaulted ceilings are supported by a self‑bearing roof terrace of opus caementicium. The site earned the nicknames “Water Cathedral” and “Cathedral of Bacoli” because of its church‑like atmosphere. Visitors entering via a restored north‑western staircase are greeted by the dramatic play of water and light: the Tyndall effect turns the cistern into a semi‑submerged cathedral where greenish shafts of light filter through the stone walls. A remarkable labyrinth‑shaped mosaic floor adorns one of the chambers, offering a glimpse into Roman artistry. Today the cistern is privately owned but remains open to the public, providing a serene escape for history lovers and architectural enthusiasts alike. Whether you are a student of ancient engineering, a casual tourist, or simply seeking a quiet spot with a touch of history, the Piscina Mirabilis offers an unforgettable glimpse into Roman ingenuity.

Highlights

• Massive Roman Cistern
• Mystic Tyndall Effect
• Barrel‑Vaulted Pillar Arrangement
• Mosaic Floor

Must-See Areas

At a glance

• Typical visit: about 30 minutes