This is one of those verses where Targum Pseudo-Jonathan on Genesis 8:20 opens a hidden corridor through the whole Torah. The Hebrew simply says Noah built an altar. The Aramaic says more. It says he built that altar which Adam had builded in the time when he was cast forth from the garden of Eden, and had offered an oblation upon it; and upon it had Kain and Habel offered their oblations. The Flood destroyed it. Noah rebuilt it on the same spot.
Pause. According to this Targum, there is one altar. Adam raised it when he was banished from Gan Eden. Cain and Abel brought their offerings to it — and we know how that ended. The altar stood through the whole generation of the Flood, silent, unused, until the waters swept it away. And now Noah finds the place, clears the mud, and rebuilds.
Jewish tradition will eventually identify that spot with Mount Moriah, the same stone where Abraham will one day bind Isaac and where the Temple will one day stand. Every altar in Jewish history is, in the Targum's imagination, the same altar.
Noah takes of every clean animal and every clean bird and offers four sacrifices. The Lord accepted his oblation with favour. The takeaway: places of true worship do not disappear. They wait. And when a righteous person returns, the stones are still there.