The Roman Empire built some of the greatest structures in history, and now, experts use cutting-edge technology to see if these cutting-edge engineering marvels could be made today. This is a mashup of S01E07, "Fortress of the Gods" and S01E03, "Ghosts of the Colosseum."

When catastrophic fires ravaged Notre-Dame Cathedral in Paris, France during April 2019, one of the world's great wonders was left in ruins. Experts use the latest tech and modern-day science to reveal what it will take to build it a second time.

Venice, Italy is a city in crisis, and it took dangerous, cutting-edge engineering to build it. As apocalyptic floodwaters unleash havoc, experts use the latest tech and modern-day science to reveal if building it a second time would be just as deadly.

Rome's Pantheon hides the secret to the Roman Empire's power, and it took dangerous, cutting-edge engineering to build it. Experts use the latest tech and modern-day science to reveal if building it a second time would be just as deadly.

The Great Wall of China is one of the world's greatest engineering marvels, and it took dangerous, cutting-edge construction to build it. Experts use the latest tech and modern-day science to reveal if building it a second time would be as deadly.

Rome's aqueducts are one of the greatest engineering marvels in history, and it took dangerous, cutting-edge construction to build them. Experts use the latest tech and modern-day science to reveal if building them a second time would be as deadly.

According to the Bible, Noah's Ark was a world-changing engineering feat, and it took cutting-edge construction to build it. Experts use the latest tech and modern-day science to reveal if building it a second time would be just as difficult.

Rome's Colosseum is the most famous stadium on the planet, and it took cutting-edge engineering and a fallen emperor to build it. Experts use the latest tech and modern-day science to reveal if building it a second time would be just as difficult.

New York's Brooklyn Bridge might be the most important bridge in the world, and it took dangerous, cutting-edge engineering to build it. Experts use the latest tech and modern-day science to reveal if building it a second time would be just as deadly.

Egypt's Great Pyramid is one of the world's greatest and most mysterious marvels, and using cutting-edge tech and the latest engineering innovations, experts reveal what it would take to build the ancient wonder today.