Detect Death

For the duration, you sense the presence of death within 300 feet of you. If you sense death in this way, you can use your action to see a faint aura around any visible dead body, and learn whether or not it may be used in Necromancy spells. 

The spell can penetrate most barriers, but it is blocked by 3 feet of stone, 3 inch of common metal, a thick sheet of lead, or 10 feet of wood or dirt.