Paris, France, May 21, 2015 / 13:37 pm

Known for its ornate rose window and towering stained glass glory, the thirteenth century Sainte-Chapelle in Paris has finally been pieced back together after a seven year laser-cleaning project.

Seven hundred and fifty years of weather effects, candle smoke, and grime had become layered and built up in Sainte-Chapelle's famous stained glass windows, causing the luminous panels to lose some of their luster.

The restoration workers who labored over cleaning the treasured stained glass called the centuries of grime the "Paris crust," which had formed on the intricate stained glass windows in the French chapel, according to a report from the BBC.

For the past seven years, over 6,000 square feet of stained glass have been carefully taken apart, piece by piece, and cleaned with the precision of laser technology – just in time for the celebration of the 800th anniversary of King Louis IX's birthday, according to the Guardian.

The crowning glory of the medieval gothic world, Sainte-Chapelle was commissioned by King Louis IX during the 1240s. The French king spent around 40,000 livres building Sainte-Chapelle, which would boast the dwelling place of Jesus' crown of thorns, along with a piece of the holy cross and other relics.

Sainte-Chapelle, meaning 'holy chapel' in French, was designed not only to house sacred relics, but also to tell the story of the Bible through the old and new testament depictions in the stained glass windows.

The striking, two-story panels portray 1,130 biblical characters – a feat which the Christian King, Louis IX, used to emphasize the importance of religion.

The French chapel has survived much more than the tedious and time-consuming project of laser cleaning. Over the centuries, Sainte-Chapelle has endured fires, floods, and dismantlings. It has also been said that during the French Revolution, the sacred chapel was transformed into an administrative office.

It wasn't until the mid-nineteenth century that the deteriorating gothic wonder of the world began to be restored to its original glory.

Although Sainte-Chapelle no longer houses the crown of thorns, King Louis IX's beloved relics can be found in Notre Dame Cathedral, only minutes away from the chapel.

In order to preserve the newly-gleaned radiance of the cleaned windows, the restorers also added a glaze of additional glass for the panels facing the outside, to protect them from future weathering,
pollution, and natural effects.

Following the laser makeover, the newly cleaned Sainte-Chapelle was re-opened to the public this year. The French chapel, an ever-popular destination in Paris, attracts almost one million people annually.