The triangle at the hoist of Cuba’s flag is red.
Cuba’s national flag has five alternating horizontal stripes—three blue and two white—and a red equilateral triangle anchored to the flagpole side. A white five-pointed star sits inside the triangle, giving the flag its Spanish nickname, Bandera de la Estrella Solitaria, or “Flag of the Lone Star.”
The design was created in 1849 by Narciso López and Miguel Teurbe Tolón during the movement for Cuban independence from Spain. The three blue stripes originally represented Cuba’s three military departments, while white symbolized the purity of the patriotic cause. The triangle’s red was associated with strength, constancy, and revolutionary symbolism.
A common mix-up is confusing Cuba’s red hoist triangle with Puerto Rico’s blue one. Puerto Rico’s flag was deliberately based on Cuba’s design with the colors of the major elements inverted: its triangle is blue and its star is white. Cuba officially adopted its flag on May 20, 1902, and the blue was standardized to a dark indigo shade in 1906.