The biggest challenges , however , lie in another direction altogether , when the line heads south for a 685-mile run to Lhasa , the capital of Tibet , over what is often called the roof of the world .
Tibet /location/location/contains Lhasa
DT JJS NNS , RB , VBP IN DT NN RB , WRB DT NN VBZ RB IN DT JJ NN TO NNP , DT NN IN NNP , IN WP VBZ RB VBN DT NN IN DT NN .
Tibet
LOCATION
Lhasa
LOCATION
/location/location/contains