Random Riddle: 6-28-2014

I am like a gigantic dragon winding through deserts, grasslands and plateaus,
and am well over 2,500 years old.

I am high, strong and massive and have a greyish-blue colour, but parts of my body are now in ruins and have disappeared, although sections of me that still remain have great historical significance.

I began as a baby dragon some 700 years before the Christ appeared on this earth, and as the years endured I grew to be an adult, all the while continuing to strengthen my keepers.

Whilst I am considered to be the longest graveyard in the world, no one is ever buried within me anymore.

What am I?
 

Riddle