Concentration camp
The people fighting for Cuban independence were guerrilla fighters.  They did not wear military uniforms and could hide themselves in groups of civilians.  They could also camp and hunt, without needing help from anybody to survive.  To keep the guerrilla fighters from being able to do these things, the Spanish government decided to put Cuban people in concentration camps.  The idea was that in the camps, Cuban people could be 'protected' by the Spanish Army until the Spanish Empire won the war.  However, this idea did not work.  At least 30% of the Cuban people in the camps died from hunger, disease, bad sanitation, and not having medicines.  Also, the concentration camps did not help the Spanish win the war.