Vatican City | A World Center of Art & Culture | Britannica

The Sala Rotonda in the Vatican Museums was designed in the late 18th century by architect Michelangelo Simonetti. Its circular space is crowned with a coffered dome, centered by a patterned marble floor based on ancient Roman designs. The room’s focal point is the immense porphyry basin, sometimes called a giant bathtub, which measures over four meters in diameter. Carved from a single block of red Egyptian porphyry, a stone reserved for imperial use in antiquity, the basin once adorned the Dom