It was exactly 80 years ago that the Long March - the strategic march of the Red Army that trudged and fought its way through thousands of miles across China - ended in the rugged, cave-riddled mountainous terrain of Yan'an in Northwest China's Shaanxi province. Yan'an was then (as it still is) something of a frontier, a waylaid place of farmers with miserable climate (stuffy summers and frigid winters), yet a place with a surprisingly delectable and distinct cuisine.

But history was made in Yan'an: the regrouping of the communist guerrillas and the ascent of Mao Zedong, eventually leading to the triumph of the revolution. It's a history that has put Yan'an on the tourist map: the sprawling revolutionary sites are visited by millions of tourists every year.

Yan'an is one of half a dozen sites in China that have become very popular tourist spots associated with the revolution. These sites have been given the collective moniker of "red tourism", which has seen dramatic growth over the past decade. Tens of millions of tourists now visit "red tourism" sites every year.