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?