As China prepares to mark 60 years of communist rule, one of the greatest challenges facing the country's rulers remains uniting China's diverse ethnic groups.

The recent unrest in Tibet and Xinjiang has shown that the issue remains a serious problem.

Out of China's 1.3 billion population, 92 per cent are ethnic Han Chinese, while the remainder are made up of 55 other officially recognised ethnic minorities, ranging from Mongols and Manchus, to Tibetans and Muslim Uighurs.

But although equal rights are promised under law, many members of minority groups say they are culturally and economically sidelined.

In the second part of Al Jazeera's series retracing the historic Long March, Melissa Chan reports from China's southwestern province of Sichuan.