The marches from Selma to Montgomery in 1965 pushed for the right to vote for all. One was named "bloody sunday" for the violent response. The protests are said to have helped create the voting rights bill which was approved the same year.
The lawrence textile strike in 1912 was a march for workers rights in lawence and pushed for the 54 hour work day.
Ghandi's Salt march in march, 1930 was a march in India to fight for India's independence from Britain. For 24 days, a mass of people walked along the Indian coast to collect salt. At the time, Indians had to buy salt from British vendors, and had to pay a tax. This started the Indian non violent civil disobedience movement.