Ruins

The Ruins was the first area in the Underground. Every fallen human entered the Ruins from a cave on Mount Ebott. Filled with dead leaves and a cool temperature, the Ruins represented the autumnal season.

Chara
After climbing Mount Ebott, Chara fell into the Ruins and called out for help.

Frisk
After resetting the timeline again, Frisk decided to stay in the Ruins with Toriel. They were taught many things, read many stories, and often bug hunted with their adoptive mother.

Entrance to Leaf Pile
The very beginning of the Ruins was a large cavern that consisted of golden flowers. The only source of light was the sun shining through a large hole in the ceiling, the first out of four spots where natural sunlight was seen in the Underground.