What took 1700 years to build?

Answer 1

The Colosseum in Rome took approximately 1700 years to complete its full structure and surrounding infrastructure, with construction starting in AD 70-80 and continuing in various stages over the centuries. While the main structure was built relatively quickly, ongoing renovations, restorations, and modifications throughout the medieval and Renaissance periods contributed to the extended timeline. Today, it stands as a symbol of ancient Roman engineering and architecture.