They were built by the Olmecs
The correct answer is C) the communist takeover in Cuba in 1959.
The event that represented a threat to U.S. national security interests during the 1950s was the communist takeover in Cuba in 1959.
The Soviet Union presence in Cuba, supporting the leadership of Cuban leader Fidel Castro, represented a threat to U.S. national security interests in the region. Cuba is so close to the Florida peninsula, and the presence of the Soviet Union on the island of Cuba worried the US government so much. This was one of the tensest moments between the United States and the Soviet Union during the Cold War years.
The abolition of slavery
The holiday is known as Juneteenth, or Juneteenth Independence Day, or also sometimes called Freedom Day. At present, 45 states continue to have observances of Junteenth day annually on June 19.
June 19 was the date on which the emancipation of slaves was announced in Texas in 1865. President Abraham Lincoln's Emancipation Proclamation (September 22, 1862) had set January 1, 1863 as the effective date for freeing all slaves in the Confederate States of America. But the Civil War had to be won to make that promise a reality. Texas was a more isolated territory in those days, and not as much involved in the main Civil War battles. There were, however, slaveholders in Texas and about a quarter-million slaves living there by 1865. General Robert E. Lee of the Confederate states had surrendered in April, 1865, but fighting in the western regions continued till June. On June 18, General Gordon Granger of the Union Army arrived in Galveston, Texas with Union troops, and on announced the emancipation of slaves. That's the background of why June 19th was chosen as the day for celebrating the actual emancipation of all slaves.
