[luckylion]

> Can you point to an engineering feat in modern times which is still functional after hundreds of years of neglect?

Why would anyone build something only to neglect it? If one of the requirements was "it shall work for 500 years and never be maintained", then I'm sure you could get plenty of things designed and built for that requirement. It's just that it's a lot more expensive and not particularly useful, so nobody bothers.