Another reminder of the sophistication of the Middle Ages was the art of stained glass. To see the best of 13th-century glass in its glorious original setting, visit the nearby church of Sainte-Chapelle.

Embedded in a historic complex of governmental buildings, the church’s muscular Gothic buttresses support the stone roof. The walls are essentially window holders for the church’s stained glass.

Stepping inside, you’re overwhelmed by the most dazzling Gothic interior anywhere. In the Bible, it’s clear: Light is divine. Let there be light. In a Gothic church, light pours through stained glass like God’s grace shining down on earth. Gothic architects used their new technology to turn dark stone buildings into lanterns of light.

In the 13th century King Louis IX obtained the supposed Crown of Thorns. He needed an appropriate place to house the precious relic. So they scrambled and built this church in just six years. Because it was built so quickly — one architect and one set of plans, almost unheard of in Gothic times — the architecture is unusually harmonious.

The altar was raised up high to better display the Crown of Thorns.

Filling the walls on all four sides, the 15 storytelling panels illustrate Bible passages from Creation in Genesis to the story of Christ. Remarkably, most of the stained glass here is original. What you’re looking at is exactly what visitors have marveled at for eight centuries.