落葉歸根。

"The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made of the interiors of collapsing stars. We are made of starstuff."

-- Carl Sagan,

In a billion years' time, our sun will explode and all that we have been, all that we have done; evidence of human civilisation, our existence, will have been for naught.
But does that matter?
Do we have to leave behind a legacy?

Such a selfish reason.
To have need and want for signs of our existence to remain.

The Chinese have an idiom for it, "落葉歸根".
Fallen leaves return to their roots.

Leaves decompose and provide nourishment for the tree in the coming months.
Endless cycles of life and death.

One day, we too will return to our roots.
Won't we?