In 1976, Israel's practice of expropriating Arab land in northern Israel to build Jewish settlements provoked Arab residents in the Galilee town of Sakhnin to protest. On March 30, the Arab residents marched to repudiate the Defense Ministry's confiscation of a parcel of farmland on the outskirts of the town. Six Arabs were killed during the violent protests.
Since then, Israeli Arabs have commemorated March 30 as "Land Day" and turned the day into a general protest against what they view as discriminatory practices by the government.
Sources: Israeli Foreign Ministry