Great Wall of China - BBC Programme

I listened to the BBC "In Our Time Programme" on the Great Wall of China the other day: https://www.bbc.co.uk/programmes/b00s3h3w

Some nice insights into the history, function etc. through the ages. 

I didn't get the Monty Python allusion, though.

The nation building usage by Sun Yatsen is particularly interesting as it points to the general efforts at the beginning of the last century to forge a unified China out of several multi-ethnic and diverse entities in the face of colonial aggression by "the West" and Japan.