Final answer:
The two monuments in the Plaza de las Tres Culturas are dedicated to the Boy Heroes and the kings and saints respectively.
Step-by-step explanation:
The two monuments in the Plaza de las Tres Culturas are dedicated to different historical figures and events.
The first monument is known as the Monument of the Boy Heroes, which is dedicated to the six young Mexican military cadets who died defending the Chapultepec Castle during the Mexican-American War of 1847.
The second monument is the Altar de Los Reyes, located in the main cathedral in Mexico City. It is dedicated to the kings and saints and is a prominent example of Churrigueresque style architecture.