This is the tunnel that's straight ahead as you enter the main room.
At this stage of the game, there's not too much to find here, but there are some things to take and note.
At the very end of the tunnel, there's a beautiful mural of a cat and a whole bunch of birds of many types. It'd be a good idea for you to use your cell phone to take a picture of the mural for later.
Embedded in this mural is a brown glazed plaque that Nancy wants to take but can't. You'll need a tool designed for prying or breaking things.
Have you been in the antiquities tent yet? You'll find what you need there.
More specifically, you need the pick.
Where do I find the pick in the tent?
Use the pick on the plaque to pry it out of the wall. You won't need it for a long time, though.
There's one more thing to find in here at this point of the game, and that too is related to something in the antiquities tent.
How do I assemble this broken amulet?
Where is the last piece of the amulet?