The Field Museum houses more than 40 million items, and some of those things the public never gets to see. But through a series of puzzles visitors can uncover one ancient piece of history hidden underneath the lakefront institution.

The museum launched an app-based puzzle game as a way to share the chapel of Netjer User, who was a chamberlain to an Egyptian pharaoh. The chapel was purchased in 1920 by the museum and during 1988 renovations, workers found it impossible to move the solid marble structure so they just built around it.

The ancient artifact is worth a visit because it is so well preserved. The red and green colors used to paint the floor-to-ceiling hieroglyphs are remarkably vivid and unlike what’s currently on view to the public.

Since the chapel isn’t in the museum’s public space, staff decided to bring visitors behind the scenes. At first they thought maybe an “escape room” challenge might work, but ultimately hired Mystery League, a company that designs puzzles for creative team building, to develop a game.

The Field Museum’s puzzle hunt lasts a few hours and takes you through the Mummies, The Ancient Americas, and Inside Ancient Egypt exhibits to search for clues. Players will be equipped with a workbook to help them solve riddles and an iPad for figuring out codes through the app which uses augmented reality (similar to how the filters work on Snapchat and Instagram).

You won’t find any hints on how to solve the puzzle here, but trust us, it isn’t easy. The game is geared toward adults (although some clever teenagers might be up to task). Ticket packages for teams of four cost $128, which includes what you need for the puzzle hunt, museum admission and a Discovery Pass for the Mummies exhibit.

There are only a few more dates for April if you’re up for the adventure.