Which of the seven hills of Rome did Michelangelo design into a piazza?

Michelangelo designed the Piazza del Campidoglio on Rome’s Capitoline Hill.

Beginning in 1536, Michelangelo reshaped the hilltop into a unified civic setting at the request of Pope Paul III. The project reorganized an irregular medieval space around the ancient equestrian statue of Marcus Aurelius, which was placed at the center of the piazza.

His design included new and remodeled palaces: the Palazzo Senatorio at the rear, the Palazzo dei Conservatori on one side, and the Palazzo Nuovo opposite it. The broad ramp called the Cordonata connected the piazza with the city below and allowed riders to ascend without dismounting.

The result is famous for its trapezoidal layout, strong central axis, and patterned paving. Michelangelo’s plan also turned the civic center away from the Roman Forum and toward the papal city. Much of the complex was completed after his death, and the paving design was not executed until the 20th century.