This is an important week for the 400,000 Roman Catholics in the Diocese of Tucson. It will be standing room only at St. Augustine Cathedral for Easter Sunday mass.

“We know it as the Gem in the Desert,” said Leilani Gomez. “This is truly a gem, truly a gem that we have here in Tucson.”

Gomez is describing the 127-year-old St. Augustine Cathedral in downtown Tucson. She is a member of the church and a docent, who gives tours of the Gem in the Desert.

“It just gives you that sense of peace,” Gomez said. “It enlightens me, it deepens my faith.”

The history of St. Augustine Cathedral actually dates back to 1732. The first catholic church in Tucson was at the base of Sentinel Peakor “A” Mountain.

As Tucson grew, so did the need for a larger church. They moved to the safety of Tucson’s Presidio San Agustin in 1776.

“It was a mission church at that time,” explained Gomez. “The priest from New Mexico would come marry, baptize or whatever needed to be done.”

The first San Agustin Cathedral was completed in 1868, just outside the Presidio, with Father Salpointe as its first pastor. Salpointe went on to become bishop, and is now the namesake of Salpointe Catholic High School in Tucson.

There’s still a plaque marking the spot of the original cathedral near Church and Broadway.

By the late 1800s, Bishop Bourgade recognized the need for an even larger cathedral and found a one-square block area to purchase just southeast of the original cathedral.

Leilani Gomez: “For $400” Pat Parris: “What a bargain.” Leilani Gomez: “‘What a bargain’ is right. It still stands as the Cathedral Square.”

The new St. Augustine Cathedral was completed in 1897.

The brick structure was transformed into its present Mexican Baroque style in 1928.

There was a major renovation done to the cathedral in 1968, but the facade and vestibule are original.

Leilani: “Breathtaking.” Pat: “When you see it, it is, right?” Leilani: “It’s breathtaking, I can tell you that.”

Gomez explained the stained glass windows on the bottom tell the story of St. Augustine. The stained glass windows on top represent all of the apostles.

The cathedral has a unique design.

“There’s a decline as you’re going down,” said Gomez. “That was purposely done so that the people sitting in the back are able to see the altar.”

The cathedral actually has three altars. On one side, on the altar is the Blessed Sacrament Chapel and on the other is a shrine to Our Lady of Guadalupe.

On the main altar is the remarkable Pamplona Crucifix.

“This crucifix dates back to the 12th Century,” Gomez explained. “Isn’t that amazing?”

The Pamplona Crucifix was refurbished in 2010 by San Xavier restoration experts Tim Lewis and Matilde Rubio.

Leilani: “Beautiful job they did.” Pat: “It’s so colorful.” Leilani: “It didn’t have color before and now it does.” Pat: “Well, it seems fitting doesn’t it.”

The Pamplona Crucifix is the centerpiece of St. Augustine Cathedral.

About the name: Is it pronounced St. Agustin or St. Augustine?

“My parents, I’m Hispanic, so they would say San Augustine,” said Gomez. “But growing up I knew it as St. Agustin. So either way.”

According to the diocese, St. Augustine Cathedral and San Xavier Mission are the two most photographed buildings in the southwest.