The monument: A semi-circle of six freestanding columns at the entrance to Mexico City’s verdant jewel, Chapultepec (Aztec for “grasshopper hill”) Park. The columns honor six teenage cadets who threw themselves to their deaths from the heights of Chapultepec Castle in 1847 rather than surrender to U.S. Marines who were about to take Mexico City in the Mexican War.

Why to go: In March 1947, as his motorcade is heading to the Mexico City Airport at the end to his official three-day state trip to Mexico, U.S. President Harry Truman suddenly orders his driver to detour to the entrance to Chapultepec Park. The 1,600-acre park, at one time a leafy, protected neighborhood for Aztec royalty, is Mexico City’s Central Park and Capitol Mall rolled into one.

Truman asks his driver to stop at the Monument to the Children Heroes. There, an aide removes a wreath from the trunk of the president’s limousine and helps him place it at the monument’s base.

The Mexicans are astonished. Almost exactly 100 years after their capital city fell to U.S. armed forces in a war they still recall bitterly, the leader of the victorious nation has spontaneously come to honor their martyrs. Witnesses to this act will remember officials, newspaper reporters and ordinary citizens breaking into tears at Truman’s gesture. Press accounts the next day will declare that the president’s tribute has almost single-handedly wiped out a century of Mexican resentment toward the United States.

Truman chose wisely. The monument to the young cadets, seen by millions of people each year, was the country’s most powerful sustainer of the lingering bitterness Mexicans felt toward the U.S.

What to add to the journey: Mexico City, for all its problems – smog, overtaxed infrastructure, crime, pollution – is still one of the most exciting places in the world. It has a sense of energy not unlike Manhattan’s. In its perpetual spring-like climate, people are in a hurry. If you’re looking for rustic charm and rural deliberation, Mexico City will disappoint.