Step inside the best-preserved building from Ancient Rome. Originally built as a temple to all gods, the Pantheon is an architectural miracle that has stood for nearly 2,000 years. Inside the Pantheon, you will experience: The Great Dome & Oculus: Look up at the largest unreinforced concrete dome in the world. You’ll see the famous 'Oculus,' the 9-meter open hole at the top that serves as the building's only light source. Royal & Artistic Tombs: Pay your respects at the final resting place of the Renaissance master Raphael, as well as the Italian Kings Vittorio Emanuele II and Umberto I. The Living Church: Discover how this pagan temple was transformed into the Basilica of St. Mary and the Martyrs in 609 AD, preserving its stunning marble floors and altars for centuries. Ancient Engineering: Admire the 16 massive Egyptian granite columns in the portico and the giant bronze doors some of the oldest and heaviest in the world.