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.

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.