Martyrs' Day is a Panamanian holiday which commemorates the January 9, 1964 riots over sovereignty of the Panama Canal Zone. The riot started after a Panamanian flag was torn down during conflict between Panamanian students and U.S. citizens living or born in the Panama Canal Zone (ie. "Zonians") over the right of the Panamanian flag to be flown alongside the U.S. flag.
U.S. Army units became involved in suppressing the violence after Canal Zone police were overwhelmed, and after three days of fighting, about 22 Panamanians and four U.S. citizens were killed. The incident is considered to be a significant factor in the U.S. decision to transfer control of the Canal Zone to Panama through the 1977 Torrijos-Carter Treaties.
