Detect Magic

For the duration, you sense the presence of magical effects within 30 feet of yourself. If you sense such effects, you can take the Magic action to see a faint aura around any visible creature or object in the area that bears the magic, and if an effect was created by a spell, you learn the spell's school of magic.

The spell is blocked by 1 foot of stone, dirt, or wood; 1 inch of metal; or a thin sheet of lead.