Clay Pipes & Tile Roofs how long do they last?

[Matt R.]

I was having this discussion with my dad, who is basically the smartest guy I know. He explained how with proper maintenance a tile roof in Cali can last hundreds of years and there are clay layed aquaducts still working over 2000 years old. He pointed to the original Spanish missions for a possible roof example. As usual his points made sense. My question is, for the Southwest folks, what is the oldest working tile roof you have encountered and or oldest working clay pipes in any location? 

thanks, 

Matt