There are many symbols within the book but three that deserve some more analysis are:

The pits

Typically pits contain monsters and this is the case here, as this is where the Martians are found. When the cylinders land, the strength of their impact creates them, and it becomes their birthplace in a manner of speaking. The pits parallel the emergence of life on Earth, becoming symbols of the birth of a new time and species. However, at the end of the story, the pit is where the Martians are laying dead. So they not only represent the start of life but also the end.

The Martians' physical appearance

First of all, the Martians are grey, which could be seen as foreshadowing. Grey is a color between the white of innocence and the start of life and the black of death. After the narrator realizes that it was bacteria that killed the Martians, he comments that since his first sight of them, they had been in demise. Also, their many tentacles are suggestive of octopuses, creatures of the deep that have long been feared by sailors and are still seen in a creepy light.

The Sun

The sun is setting when the Martians take their first victim. Then there is a period of darkness, when they are killing men and setting out to take over the world. When the narrator discovers them dead, the sun is rising. Light and hope have returned and men no longer have to live in fear.