I have worked at One City Center for over 15 years and have walked by this big rock on Temple Street outside the building hundreds of times. I never realized until now that it's not a rock. 

If you're ever on Temple street in front of the parking garage near the Nickelodeon Theater, stop for a minute to look a this big rock right outside of The Works and you'll learn something amazing about Portland's history.

When you get closer, you'll quickly discover this isn't a rock at all...

WJBQ.com

This is the Elm Theater Mask, a piece of the Elm Theater that stood on the Elm Street side of where the Portland Public Library stands today. The building was torn down in 1952 and when excavation began 25 years later for the Portland Public Library, it was found. It was later moved to Temple Street as a monument, left in the state it was found.

WJBQ.com

The plaque at the mask tells the story...

Elm Theater Mask

This mask was found in 1977 during the excavation of the Portland Public Library at Elm and Congress Streets. It was the single - most important architectural detail of the former Elm Theater. The Elm Theater, which stood at its Elm Street site from 1916 to 1952, was the work of architects William R. Miller and Raymond J. Mayo of Portland. The Beaux-Arts style building served as a motion-picture house and later as a church, a theater for WW II troops and a playhouse for the Portland Players. The mask has been intentionally left in its "found" state.

I did some digging and found an old photo on Maine Memory Network of the Elm Theater from 1920.

Maine Memory Network

 Here's what this area looks like today...

Google Street View

So where's the mask on the old theater? You've got to zoom in real close, but here it is...

Maine Memory Network

I can't believe that this amazing piece of Portland history has been sitting right under my nose for years.