So you turn your back upon Peking, and the railway takes you to Kalgan on the edge of the great plateau.

From Kalgan they travelled westwards to Taitong, where the wall was not so high.

The outer (northern) wall passes through Kalgan, thus guarding the pass into Mongolia.

I must buy ponies to cross from Kalgan; camels were the only thing to use; no camels could be had in summer.