An historic Catholic cathedral, the first built in the United States after the signing of the Constitution, will reopen this week after a two-year, $32-million renovation.

The Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary in Baltimore will reopen Saturday with a special ceremony.

The restoration, managed by the Basilica Historic Trust, uncovered a number of architectural and artistic treasures that had been covered up over the basilica’s 200-year history, including 24 skylights and murals of Matthew, Mark, Luke and John. The 1940s stained-glass windows were replaced with clear glass. Modern heating, lighting and electrical systems were also installed.

Those who visited the cathedral earlier this week on a special pre-opening tour remarked on the brightness and more cheerful aspect of the church, reported The Baltimore Sun.

At a press conference, Cardinal William Keeler thanked the architects, contractors and artisans who worked on the basilica, which he described as "an American treasure."

Cardinal Keeler told reporters that the first archbishop, John Carroll, "wanted a cathedral that would celebrate the newly acquired right of Catholics and people of other faiths to worship openly, in accord with their conscience," following the signing of the Constitution. The cornerstone of the basilica was laid in 1806.

Preparation for the renovation and restoration began nearly a decade ago and included plans to upgrade the infrastructure and to construct elements of the original design, by renowned British-American architect and engineer Benjamin Henry Latrobe, which were never realized, reported The Baltimore Sun.  Latrobe also designed the U.S. Capitol building.

For example, contractors excavated four to 15 feet to build a chapel in the basilica, named Our Lady Seat of Wisdom Chapel, which was in the original plans but was never built.