Detect Portal

For the duration, you can sense the presence and location of portals or pathways within 30 feet of you.  You can also sense if a portal or pathway was used within the last 24 hours.  The spell only detects portals or pathways that exist in a permanent state and does not convey any ability to discern how the portal or pathway is opened or operated, only that it exists.  The spell can penetrate most barriers, but is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.

At higher levels.  When you cast this spell using a spell slot of 2nd level or higher, you are also able to discern the sigil sequence, key, or any pass phrases required to operate the portal.  When you cast this spell using a spell slot of 3rd level or higher, you are also able to discern which plane of existence the portal's destination resides on and general information about the area surrounding it up to a 30 feet radius.