War Of The Worlds by H.G. Wells (Chapters 4-12)

"It was sweeping round slowly and steadily, this flaming death, this invisible, inevitable sword of heat." (39)
A ray that can kill without seeing, massive machines that tower over even the tallest buildings, and a taste for death and destruction. These are the weapons the Martians have leveled against the human population of Earth, attempting to destroy them for their land. Earth is a fertile place, and the Martians have set their sights on it. Like the European colonists must have seemed to the natives of Africa and America with their guns and horses (Cortez), the Martians simply overwhelm the first Earthlings they encounter with sheer surprise. Although it is not mentioned in the book, if this were to happen today, I'm sure that there would people who would take it as a sign that God was punishing the people of Earth for their wickedness. That's also similar to the Aztecs, who initially worshipped Cortez as a god, because their prophesies foretold of a light-skinned god with flaming red hair. The Martians rain death and destruction wherever they go, not to dissimilarly to the Angels of Death from the Old Testament and Book of Revelation.
The panic associated with the alien attack actually happened in real life, also. In 1938, the actor and director Orson Welles performed an adaptation of War of the Worlds on the radio. Many listeners took it as a real report of an alien attack, and in some places, especially in New Jersey, there was widespread panic. People were already on edge because of the tensions in Europe that would eventually lead to World War II, and some listeners believed it was actually the Germans, not the Martians attacking. That broadcast was an good example of how an alien attack may actually play out if it happened today.