This is the first-known photograph of the finished "A" on Sentinel Peak. Photo Courtesy of UA Special Collections. Listen:
The University of Arizona celebrated a football victory over California's Pomona College on Thanksgiving Day in 1914.
That led to the construction of the giant letter that's been a popular landmark ever since.
A civil engineering student, who was also a member of the football team, suggested constructing the A on Sentinel Peak.
Dozens of students and staff members joined him. They finished the project by whitewashing the rock and mortar combination on March 4, 1916.
Since then, the A has been a memorable symbols for countless students, visitors and residents.
Terry Ruiz was born and raised in Tucson and while she didn't know the A was finished 100 years ago, the project is dear to her heart.
"The A has been a place that we've always come to and brought our kids. I've come here since I was really, really young," Ruiz said.
"When we leave town and then we're on our way home, I know I'm home once I see the A."
According to information from the university, the rock, mortar and water were taken to Sentinel Peak by six-horse teams, and the total cost of the transportation, materials and equipment was $397.
Since it was finished, "A Mountain" has become a common name for Sentinel Peak.
We'd like to know what the "A" means to you. Join the conversation on Twitter or Facebook with #SentinelPeakA
The "A" on Sentinel Peak was completed in 1916 and has become one of the most recognizable landmarks in Southern Arizona. 
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