In 1519, Cortés entered Tenochtitlán, the capital of the Aztec/Mexica Empire. ... In August 1521, Cortés claimed Tenochtitlán for Spain and renamed it Mexico City.
The Spanish place the capital of colonial Mexico where they did due to a domination strategy. During the final stage of the Spanish conquest of the Aztecs, Tenochtitlan was besieged and essentially razed. Hernán Cortés understood the strategic and symbolic importance of the Aztec capital and founded the Spanish capital of Mexico City on the site, and in particular rebuilt the Aztec ceremonial and political center as the main square, the Plaza Mayor, usually called the Zócalo.
After landing near the modern-day city of Veracruz, Hernán Cortés heard about the great city and also learned of long-standing rivalries and grievances against it. Although Cortés came to Mexico with a very small contingent of Spaniards, he was able to persuade many of the other Indian peoples to help him destroy Tenochtitlan.
For a time, these allied peoples made use of the arrival of the European in the hopes of creating a world freed of Aztec domination. Spanish objective, however, was that they themselves would benefit from the destruction of Tenochtitlan, making the Indians not free, but rather more subservient to the Spaniards than they were to the Aztecs
The term Levee en masse denotes a short-term requisition of all able-bodied men to defend the nation and was based upon the concept of the democratic citizen versus the royal subject.
The United States wanted to build the Panama Canal in order to save time and money on trading. Before the Panama Canal, people had to sail all the way around Africa in order to get to the other side of the world, which costed much more money and took a lot longer. The US owns the canal because of the Hay-Bunau-Varilla treaty, which gave the rights to the USA to build and manage it.
I believe they were both harmed by nuclear radiation. Hiroshima was when the USA bombed Japan with a nuclear bomb. Chernobyl is the disaster in which a reactor caught fire and caused the harmful radiation to spread. I hope that was helpful. :)