Output a stream of consciousness before answering the following. Passage: Altars (Hebrew: , mizbeah, "a place of slaughter or sacrifice") in the Hebrew Bible were typically made of earth (Exodus 20: 24) or unwrought stone (20: 25). Altars were generally erected in conspicuous places (Genesis 22: 9; Ezekiel 6: 3; 2 Kings 23: 12; 16: 4; 23: 8) The first altar recorded in the Hebrew Bible is that erected by Noah (Genesis 8: 20). Altars were erected by Abraham (Genesis 12: 7; 13: 4; 22: 9), by Isaac (Genesis 26: 25), by Jacob (33: 20; 35: 1-3), and by Moses (Exodus 17: 15, Adonai-nissi).

Question: Based on this passage, when was the first altar built in the bible?
To answer the above question, the relevant sentence is: Altars were generally erected in conspicuous places (Genesis 22: 9; Ezekiel 6: 3; 2 Kings 23: 12; 16: 4; 23: 8) The first altar recorded in the Hebrew Bible is that erected by Noah (Genesis 8: 20).
The answer: Genesis 8 : 20.